Cross-linked surface coating and interfacial layer for perovskite material photovoltaic device

Abstract

To provide a PV that can incorporate a layer of perovskite material as a photoactive layer that generates electricity when exposed to light, and to allow an additional layer within a PV device to assist in the transport of charge from the photoactive layer, wherein the choice of the charge transport layer can affect the performance and durability of the PV device.SOLUTION: A photovoltaic device includes a photoactive material including a perovskite material, and an interfacial layer including a cross-linked polymer including a fullerene or a fullerene derivative, a cross-linker, and one or more polymers selected from the group consisting of polystyrene, [6,6]-phenyl-C61-butyric acid methyl ester, poly(4-vinylphenol), [6,6]-phenyl-C61-butyric acid, and any combination thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 941,320, entitled "Cross-Linked Surface Coatings and Interfacial Layers for Perovskite Material Photovoltaic Devices," filed November 27, 2019, the contents of which are incorporated herein by reference in their entirety. [Background technology]

[0002]

[0002] The use of photovoltaics (PV) to generate electricity from solar energy or radiation can offer many benefits, such as power supply, low or no emissions, power production independent of the power grid, durable physical structure (no moving parts), stable and reliable system, modular construction, relatively quick installation, safe to manufacture and use, and favorable public opinion and acceptance for use.

[0003]

[0003] PVs can incorporate a layer of perovskite material as a photoactive layer that generates electricity when exposed to light. Additional layers within the PV device can assist in the transport of charge from the photoactive layer. The choice of charge transport layer can affect the performance and durability of the PV device.

[0004]

[0004] The features and advantages of the present disclosure will be readily apparent to those skilled in the art, and many modifications may be made by those skilled in the art that fall within the spirit and scope of the present invention. Summary of the Invention

[0005]

[0005] In one embodiment, a method for fabricating a perovskite material photovoltaic device includes depositing a perovskite material, depositing a layer of fullerene, depositing a halosilylalkane, and heating an alkyl hydroxide to bond the halosilylalkane to the fullerene.

[0006]

[0006] In one embodiment, the crosslinked polymer comprises a halosilylalkane and one or more monomers selected from the group consisting of polystyrene, [6,6]-phenyl-C61-butyric acid methyl ester, poly(4-vinylphenol), [6,6]-phenyl-C61-butyric acid, and combinations thereof.

[0007] In some embodiments, a photovoltaic device includes a photoactive material comprising a perovskite material. The photovoltaic device also includes an interfacial layer comprising a crosslinked polymer including a halosilylalkane and one or more monomers selected from the group consisting of polystyrene, [6,6]-phenyl-C61-butyric acid methyl ester, poly(4-vinylphenol), [6,6]-phenyl-C61-butyric acid, and combinations thereof. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a typical photovoltaic (PV) cell including an active layer, according to an embodiment of the present disclosure. [Figure 2]

[0009] FIG. 1 is a stylized diagram illustrating components of an exemplary PV device, according to an embodiment of the present disclosure. [Figure 3]

[0010] FIG. 1 is a stylized diagram illustrating components of an exemplary apparatus, according to an embodiment of the present disclosure. [Figure 4]

[0011] FIG. 1 is a stylized diagram illustrating components of an exemplary apparatus, according to an embodiment of the present disclosure. [Figure 5]

[0012] FIG. 1 is a stylized diagram showing the diagram of Ruddlesden-Popper perovskite. [Figure 6]

[0013] FIG. 1 is a stylized diagram showing an illustration of a perovskite material doped with alkylammonium cations, according to an embodiment of the present disclosure. [Figure 7]

[0014] FIG. 1 is a stylized diagram showing a representation of a perovskite material with a 1-butylammonium surface layer, according to an embodiment of the present disclosure. [Figure 8]

[0015] FIG. 1 is a stylized diagram showing an illustration of a perovskite material with a surface layer of multiple bulky organic cations, according to an embodiment of the present disclosure.

[0016] FIG. 8A is a stylized diagram showing an illustration of a perovskite material with a surface layer of multiple bulky organic cations, according to an embodiment of the present disclosure. [Figure 9]

[0017] FIG. 1 is a comparative illustration of images taken of perovskite materials with and without a 1-butylammonium (“BAI”) surface coating, according to certain embodiments of the present disclosure. [Figure 10]

[0018] FIG. 1C is a stylized diagram showing comparative examples of images taken of perovskite materials with and without a 1-butylammonium (“BAI”) surface coating, according to certain embodiments of the present disclosure. [Figure 11]

[0019] Figures A-D show various perylene monoimides and diimides that can be applied to the surface of perovskite materials according to certain embodiments of the present disclosure. [Figure 12]

[0020] FIG. 1 is a stylized diagram showing an illustration of the addition of perylene monoimide ammonium cations to a perovskite material, according to certain embodiments of the present disclosure. [Figure 13]

[0021] FIG. 1 is a stylized diagram showing an illustration of 1,4-diammonium butane incorporated into the crystal lattice of a lead iodide perovskite material, according to an embodiment of the present disclosure. [Figure 14]

[0022] FIG. 1 is an illustration of X-ray diffraction peaks (XRD) of perovskites with various concentrations of 1,4-diammonium butane, according to an embodiment of the present disclosure. [Figure 15]

[0023] 1 provides time-lapse images of perovskite material samples with various concentrations of 1,4-diammoniumbutane, according to an embodiment of the present disclosure. [Figure 16]

[0024] FIG. 1 is a diagram of a polyammonium alkyl cation, according to an embodiment of the present disclosure.

[0025] FIG. 16A is a stylized diagram showing a schematic of 1,8 diammonium octane incorporated into the crystal lattice of a formamidinium lead iodide perovskite material, according to an embodiment of the present disclosure.

[0026] FIG. 16B is an illustration of bis(4-aminobutyl)-ammonium incorporated into the crystal lattice of a lead iodide perovskite formamidinium material, according to an embodiment of the present disclosure.

[0027] FIG. 16C is an illustration of tris(4-aminobutyl)-ammonium incorporated into the crystal lattice of a formamidinium lead iodide perovskite material, according to an embodiment of the present disclosure. [Figure 17]

[0028] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 18] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 19] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 20] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 21] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 22] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 23] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 24] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 25] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 26] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 27] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 28] 1A-1C are diagrams of structures of certain organic molecules, according to certain embodiments of the present disclosure. [Figure 29]

[0029] 1 shows an X-ray diffraction pattern of a perovskite material according to an embodiment of the present disclosure. [Figure 30]

[0030] FIG. 1 is a stylized representation of the thickness of the inorganic metal halide sublattice of a perovskite material, according to an embodiment of the present disclosure. [Figure 31]

[0031] 1 shows optical and photoluminescence images of a perovskite material photovoltaic device according to certain embodiments of the present disclosure; [Figure 32]

[0032] 1 shows the power output curve of a perovskite material photovoltaic device according to an embodiment of the present disclosure. [Figure 33]

[0033] FIG. 1 shows the current-voltage (IV) scan of a perovskite material photovoltaic device according to an embodiment of the present disclosure. [Figure 34]

[0034] Figure 1 shows box plots for open circuit voltage, short circuit current density, fill factor, and power conversion efficiency of perovskite material photovoltaic devices according to certain embodiments of the present disclosure. [Figure 35]

[0035] 1 shows the external quantum efficiency (EQE) curves of perovskite material photovoltaic devices according to certain embodiments of the present disclosure. [Figure 36]

[0036] 1 shows an admittance spectroscopy plot of a perovskite material photovoltaic device according to an embodiment of the present disclosure; [Figure 37]

[0037] FIG. 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 38]

[0038] 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 39]

[0039] 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 40]

[0040] 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 41]

[0041] FIG. 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 42]

[0042] 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 43]

[0043] 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 44]

[0044] 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. [Figure 45]

[0045] FIG. 1 illustrates the structure of a crosslinked interfacial layer according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009]

[0046] Improvements in various aspects of PV technology that are compatible with organic, inorganic, and / or hybrid PVs are expected to further reduce the costs of both organic and other PVs. For example, certain solar cells, such as perovskite PV solar cells, can utilize novel cost-effective and stable alternative components, such as nickel oxide interfacial layers. Furthermore, various types of solar cells may advantageously include chemical additives and other materials that are, among other things, more cost-effective and durable than currently existing conventional options.

[0010]

[0047] The present disclosure relates generally to compositions of matter, devices, and methods of using materials in solar cells in generating electrical energy from solar radiation. More specifically, the present disclosure relates to compositions of matter, photoactive materials, and other materials, as well as devices, methods of use, and formation of such compositions of matter.

[0011]

[0048] Some or all of the materials according to certain embodiments of the present disclosure may be advantageously used in any organic or other electronic device, including, but not limited to, batteries, field effect transistors (FETs), light emitting diodes (LEDs), nonlinear optical devices, memristors, capacitors, rectifying antennas, and / or rectifying antennas.

[0012]

[0049] In some embodiments, the present disclosure may provide PV and other similar devices (e.g., batteries, hybrid PV cells, multi-junction PVs, FETs, LEDs, X-ray detectors, gamma ray detectors, photodiodes, CCDs, etc.). In some embodiments, the devices may include improved active materials, interfacial layers (IFLs), and / or one or more perovskite materials. The perovskite materials may be incorporated into a variety of one or more aspects of the PV or other devices. Perovskite materials according to certain embodiments may have the general formula CMX3, where C comprises one or more cations (e.g., amines, ammonium, phosphonium, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds), M comprises one or more metals (including Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr), and X comprises one or more anions. Perovskite materials according to various embodiments are described in more detail below.

[0013]

[0050] Solar cells and other electronic devices Certain PV embodiments can be described with reference to an exemplary illustration of a solar cell, such as that shown in FIG. 1 . An exemplary PV architecture according to certain embodiments may be substantially in the form of substrate-anode-IFL-active layer-IFL-cathode. The active layer of certain embodiments may be photoactive and / or include photoactive materials. Other layers and materials may be utilized in the cell as known in the art. Furthermore, it should be noted that the use of the term “active layer” is not meant to explicitly or implicitly limit or otherwise define the properties of any other layers. For example, in certain embodiments, either or both IFLs may also be active, as long as they are semiconductors. In particular, referring to FIG. 1 , a stylized generic PV cell 1000 is shown, illustrating the high interfacial properties of certain layers within the PV. PV 1000 represents a general architecture that may be applicable to certain PV devices, such as perovskite material PV embodiments. The PV cell 1000 includes a transparent substrate layer 1010, which may be glass (or a similar material transparent to solar radiation), allowing solar radiation to pass through the layer. The transparent layer in some embodiments is also referred to as a superstrate or substrate (e.g., similar to substrate layer 3901 in FIG. 2 ) and may comprise any one or more of a variety of rigid or flexible materials, such as glass, polyethylene, polypropylene, polycarbonate, polyimide, PMMA, PET, PEN, Kapton, or quartz. In general, the term “substrate” is used to refer to the material onto which a device is deposited during fabrication. The photoactive layer 1040 may be composed of an electron donor or p-type material, and / or an electron acceptor or n-type material, and / or an ambipolar semiconductor exhibiting both p-type and n-type material properties, and / or an intrinsic semiconductor exhibiting neither n-type nor p-type properties. The photoactive layer 1040, in some embodiments, may be a perovskite material as described herein. 1, the active or photoactive layer 1040 is sandwiched between two conductive electrode layers 1020 and 1060. In FIG. 1, the electrode layer 1020 may be a transparent conductor such as tin-doped indium oxide (ITO material) or other materials described herein. In other embodiments, the second substrate 1070 and the second electrode 1060 may be transparent.As noted above, the active layer in some embodiments is not necessarily photoactive, although in the device shown in FIG. 1 it is. The electrode layer 1060 may be an aluminum material or other metal, or another conductive material such as carbon. Other materials may be used as known in the art. The cell 1010 also includes an interfacial layer (IFL) 1030, shown in the example of FIG. 1. The IFL may assist in charge separation. In other embodiments, the IFL 1030 may include a multilayer IFL, which will be described in more detail below. Also, adjacent to the electrode 1060 may be an IFL 1050. In some embodiments, the IFL 1050 adjacent to the electrode 1060 may also, or instead, include a multilayer IFL (again, described in more detail below). An IFL according to some embodiments may be semiconducting in nature, intrinsic, ambipolar, p-type, or n-type, or may be dielectric in nature. In some embodiments, the IFL on the cathode side of the device (e.g., IFL 1050 as shown in FIG. 1) can be p-type, and the IFL on the anode side of the device (e.g., IFL 1030 as shown in FIG. 1) can be n-type. However, in other embodiments, the cathode side IFL can be n-type and the anode side IFL can be p-type. Cell 1010 can be attached to electrical leads by electrodes 1060 and 1020 and a discharge unit such as a battery, motor, capacitor, power grid, or any other electrical load.

[0014]

[0051] Various embodiments of the present disclosure result in improved materials and / or designs in various aspects of solar cells and other devices, including, inter alia, active materials (including hole transport and / or electron transport layers), interfacial layers, and overall device design.

[0015]

[0052] interfacial layer In some embodiments, the present disclosure provides advantageous materials and designs for one or more interfacial layers in a PV, including thin-film coated IFLs, which can be used in one or more IFLs of a PV according to various embodiments described herein.

[0016]

[0053] In various embodiments, a device may include no interfacial layers, although it may include any interfacial layer between any two other layers and / or materials. For example, a perovskite material device may include zero, one, two, three, four, five, or more interfacial layers (e.g., the exemplary device of FIG. 2 includes five interfacial layers 3903, 3905, 3907, 3909, and 3911). An interfacial layer may include any suitable material for enhancing charge transport and / or collection between two layers or materials, and may also help prevent or reduce the possibility of charge recombination after charge is transferred from one of the materials adjacent to the interfacial layer. An interfacial layer may further homogenize the substrate physically and electrically to create changes in its roughness, dielectric constant, adhesion, defects (e.g., charge traps, surface states), or quenching.Suitable interface materials include Ag, Al, Au, B, Bi, Ca, Cd, Ce, Co, Cu, Cu, Fe, Ga, Ge, H, In, Mg, Mn, Mo, Nb, Ni, Pt, Sb, Sc, Si, Sn, Ta, Ti, V, W, Y, Zn, Zr, carbides of any of the above metals (e.g., SiC, Fe3C, WC, VC, MoC, NbC), silicides of any of the above metals (e.g., Mg2Si, Si2, Sn2Si), oxides of any of the above metals (e.g., alumina, silica, Transparent conductive oxides ("TCO(s)") such as titanium dioxide, SnO2, ZnO, NiO, ZrO2, HfO2, indium tin oxide, aluminum doped zinc oxide (AZO), cadmium oxide (CdO), fluorine doped tin oxide (FTO), sulfides of any of the above metals (e.g., CdS, MoS2, SnS2), nitrides of any of the above metals (e.g., GaN, Mg3N2, TiN, BN, Si3N4), selenides of any of the above metals (e.g., C dSe, FeSe2, ZnSe), tellurides of any of the above metals (e.g., CdTe, TiTe2, ZnTe), phosphides of any of the above metals (e.g., InP, GaP, GaInP), arsenides of any of the above metals (e.g., CoAs3, GaAs, InGaAs, NiAs), antimonides of any of the above metals (e.g., AlSb, GaSb, InSb), halides of any of the above metals (e.g., CuCl, CuI, BiI3), (e.g., CuSCN, AuCN, Fe(SCN)2), carbonates of any of the foregoing metals (e.g., CaCO3, Ce2(CO3)3), functionalized or non-functionalized alkylsilyl groups; graphite; graphene; fullerenes; carbon nanotubes; any mesoporous material and / or interfacial material discussed elsewhere herein; and combinations thereof (including, in some embodiments, bilayers, trilayers, or multilayers of combination materials). In some embodiments, the interfacial layer may comprise a perovskite material. Additionally, the interfacial layer may comprise doped embodiments of any of the interfacial materials described herein (e.g., Y-doped ZnO, N-doped single-walled carbon nanotubes).The interfacial layer may also include a compound comprising three of the above materials (e.g., CuTiO3, Zn2SnO4) or a compound comprising four of the above materials (e.g., CoNiZnO), which may exist in planar, mesoporous (porous), or other nanostructured morphologies (e.g., rods, spheres, flowers, cones (pyramids)), or aerogel structures.

[0017]

[0054] First, as described above, one or more IFLs (e.g., one or both of IFLs 2626 and 2627 shown in FIG. 1 ) may comprise a photoactive organic compound of the present disclosure, either as a self-assembled monolayer (SAM) or as a thin film. When a photoactive organic compound of the present disclosure is applied as a SAM, it may comprise a linking group through which it can be covalently or otherwise bonded to the surface of either or both of the anode and cathode. In some embodiments, the linking group may comprise any one or more of COOH, SiX (where X can be any moiety suitable for forming ternary silicon compounds such as Si(OR) and SiCl), SO, PO, OH, CHX (where X can comprise a Group 17 halide), and O, and the linking group may be covalently or otherwise bonded to an electron-withdrawing moiety, an electron-donating moiety, and / or a core moiety. The binding groups may be attached to the electrode surface to form a directionally organized layer of a single molecule (or, in some embodiments, multiple molecules) thick (i.e., when multiple photoactive organic compounds are attached to the anode and / or cathode). As described above, the SAMs may be attached via covalent interactions, but in some embodiments, they may be attached via ionic, hydrogen bonding, and / or dispersion (i.e., van der Waals) interactions. Furthermore, in some embodiments, upon light exposure, the SAMs can enter a zwitterionic excited state, thereby generating a highly polarized IFL capable of directing charge carriers from the active layer to an electrode (e.g., an anode or cathode). In some embodiments, this enhanced charge carrier injection is achieved by electronically poling the cross-section of the active layer, thereby increasing the drift velocity of charge carriers toward each electrode (e.g., holes to the anode, electrons to the cathode). Molecules for anode applications in some embodiments may comprise a tunable compound that includes a primary electron-donating moiety attached to a core moiety, which in turn is attached to an electron-withdrawing moiety and attached to a binding group. For cathode applications according to certain embodiments, an IFL molecule may comprise a tunable compound including an electron-deficient moiety bound to a core moiety, which is bound to an electron-donating moiety and to a binding group.When photoactive organic compounds are used as IFLs according to the embodiments, they may retain photoactive properties, but in some embodiments may not be photoactive.

[0018]

[0055] Metal oxides can be used in certain thin-film IFLs and may include semiconductor metal oxides, such as NiO, SnO2WO3, VO5, or MoO3. In embodiments where the second (e.g., n-type) active material includes TiO2 coated with a thin-film coated IFL including Al2O3, the coating can be formed, for example, from a precursor material such as Al(NO3)3·xH2O or any other material suitable for depositing Al2O3 on TiO2, followed by thermal annealing and dye coating. In exemplary embodiments where a MoO3 coating is used instead, the coating can be formed from a precursor material such as Na2MO4·2H2O; a VO5 coating according to some embodiments can be formed from a precursor material such as NaVO3; and a WO3 coating according to some embodiments can be formed from a precursor material such as NaWO4·H2O. The concentration of the precursor material (e.g., Al(NO3)3·xH2O) can affect the final film thickness (here, Al2O3) deposited on the TiO2 or other active material. Therefore, varying the concentration of the precursor material can be a way to control the final film thickness. For example, increasing the concentration of the precursor material can result in a thicker film. A larger film thickness does not necessarily result in a higher PCE for a PV device including the metal oxide coating. Thus, in one embodiment, the method can include coating the TiO2 (or other mesoporous) layer with a precursor material having a concentration in the range of about 0.5-10.0 mM, while other embodiments can include coating the layer with a precursor material having a concentration in the range of about 2.0-6.0 mM, or in other embodiments, about 2.5-5.5 mM.

[0019]

[0056] Additionally, while described herein with reference to Al2O3 and / or alumina, it should be noted that various ratios of aluminum and oxygen can be used to form the alumina. Thus, while certain embodiments described herein are described with reference to Al2O3, the description is not intended to prescribe a specific ratio of aluminum to oxygen. Rather, embodiments may include any one or more aluminum oxide compounds, each having an aluminum oxide ratio of AlxOy, where x may be any value, integer or non-integer, between about 1 and 100. In certain embodiments, x may be about 1 to 3 (and, again, need not be an integer). Similarly, y may be any value, integer or non-integer, between 0.1 and 100. In certain embodiments, y may be between 2 and 4 (and, again, need not be an integer). Furthermore, in various embodiments, various crystalline forms of AlxOy may be present, such as alpha, gamma, and / or amorphous forms of alumina.

[0020]

[0057] Similarly, the compounds of NiO, MoO3, WO3, and V2O5 herein may alternatively or additionally be represented as NixOy, MoxOy, WxOy, and VxOy, respectively. For each of MoxOy and WxOy, x may be any value, integer or non-integer, between about 0.5 and 100, and in some embodiments, between about 0.5 and 1.5. Similarly, y may be any value, integer or non-integer, between about 1 and 100. In some embodiments, y may be any value between about 1 and 4. For VxOy, x may be any value, integer or non-integer, between about 0.5 and 100, and in some embodiments, it may be an integer or non-integer value between about 1 and 10. In some embodiments, x and y may be values ​​that are non-stoichiometric. It should be noted that any IFL material described in this disclosure as a stoichiometric formulation may also exist in a non-stoichiometric formulation as in the examples above.

[0021]

[0058] In some embodiments, the IFL may comprise a titanate. Titanates according to some embodiments may have the general formula M'TiO3, where M' is any two + cations. In some embodiments, M' may include the cationic form of Be, Mg, Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn, or Pb. In some embodiments, the IFL may include a single species of titanate, while in other embodiments, the IFL may include two or more different species of titanate. In one embodiment, the titanate may be represented by the formula SrTiO3. In other embodiments, the titanate may be represented by the formula BaTiO3. In yet other embodiments, the titanate may be represented by the formula CaTiO3.

[0022]

[0059] For purposes of illustration, and without any limitation, titanates have a perovskite crystal structure and strongly seed the growth transformation process of perovskite materials (e.g., methylammonium lead iodide (MAPbI3) and formamidinium lead iodide (FAPbI3)). Titanates also generally meet other IFL requirements, such as ferroelectric behavior, sufficient charge carrier mobility, optical transparency, matching energy levels, and high dielectric constants.

[0023]

[0060] In other embodiments, the IFL may comprise a zirconate. In some embodiments, the zirconate may have the general formula M'ZrO3, where M' is any two + cations. In some embodiments, M' may include the cationic form of Be, Mg, Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn, or Pb. In some embodiments, the IFL may include a single species of zirconate, while in other embodiments, the IFL may include two or more different species of zirconate. In one embodiment, the zirconate may be represented by the formula SrZrO3. In another embodiment, the zirconate may be represented by the formula BaZrO3. In yet another embodiment, the zirconate may be represented by the formula CaZrO3.

[0024]

[0061] For purposes of illustration, and without any limitation, zirconates have a perovskite crystal structure and are strong seeding agents for the perovskite material (e.g., MAPbI3, FAPbI3) growth transformation process. Zirconates also generally meet other IFL requirements, such as ferroelectric behavior, sufficient charge carrier mobility, optical transparency, matching energy levels, and high dielectric constants.

[0025]

[0062] In other embodiments, the IFL may include a stannate. The stannate according to some embodiments may have the general formula M'SnO3, or M'2SnO4, where M' is any two + cations. In some embodiments, M' may include the cationic form of Be, Mg, Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn, or Pb. In some embodiments, the IFL may include a single species of stannate, and in other embodiments, the IFL may include two or more different species of stannate. In one embodiment, the stannate may be represented by the formula SrSnO3. In another embodiment, the stannate may be represented by the formula BaSnO3. In yet another embodiment, the stannate may be represented by the formula CaSnO3.

[0026]

[0063] For purposes of illustration, and without any limitation, stannates have a perovskite crystal structure and strongly seed the perovskite material (e.g., MAPbI3, FAPbI3) growth conversion process. Stannates also generally meet other IFL requirements, such as ferroelectric behavior, sufficient charge carrier mobility, optical transparency, matching energy levels, and high dielectric constants.

[0027]

[0064] In other embodiments, the IFL may include a plumbate. The plumbate according to some embodiments may have the general formula M'PbO3, where M' is any two +cations. In some embodiments, M' may include the cationic form of Be, Mg, Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn, or Pb. In some embodiments, the IFL may include a single type of plumbate, and in other embodiments, the IFL may include two or more different types of plumbate. In one embodiment, the plumbate may have the formula SrPbO3. In other embodiments, the plumbate may have the formula BaPbO3. In yet another embodiment, the plumbate may have the formula CaPbO3. In yet another embodiment, the plumbate may have the formula Pb II Pb IV It can be represented as O3.

[0028]

[0065] By way of illustration, and without implying any limitation, plumbates have a perovskite crystal structure and strongly seed the growth transformation process of perovskite materials (e.g., MAPbI3, FAPbI3). Plumbates also generally meet other IFL requirements, such as ferroelectric behavior, sufficient charge carrier mobility, optical transparency, matching energy levels, and high dielectric constants.

[0029]

[0066] Furthermore, in other embodiments, the IFL may be a compound having the general formula M'[ZrxTi 1-x ]O3 (wherein X is greater than 0 but less than 1, and M' is any 2 + In some embodiments, M' may comprise a cationic form of Be, Mg, Ca, Sr, Ba, Ni, Zn, Cd, Hg, Cu, Pd, Pt, Sn, or Pb. In some embodiments, the IFL may comprise a single species of zirconate, and in other embodiments, the IFL may comprise two or more different species of zirconate. In one embodiment, the zirconate / titanate combination has the formula Pb[ZrxTi 1-x ]O3. In another embodiment, the zirconate / titanate combination is represented by the formula Pb[Zr 0.52 Ti 0.48 ]O3.

[0030]

[0067] For purposes of illustration, and without any limitation, zirconate / titanate combinations have a perovskite crystal structure and strongly seed the growth transformation process of perovskite materials (e.g., MAPbI3, FAPbI3). Zirconate / titanate combinations also generally meet other IFL requirements, such as ferroelectric behavior, sufficient charge carrier mobility, optical transparency, matching energy levels, and high dielectric constants.

[0031]

[0068] In other embodiments, the IFL may comprise a niobate. Niobates according to some embodiments may have the general formula M'NbO3, where M' is any one of + cations. In some embodiments, M' may include the cationic form of Li, Na, K, Rb, Cs, Cu, Ag, Au, Tl, ammonium, or H. In some embodiments, the IFL may include a single species of niobate, while in other embodiments, the IFL may include two or more different species of niobate. In one embodiment, the niobate is represented by the formula LiNbO3. In another embodiment, the niobate may be represented by the formula NaNbO3. In yet another embodiment, the niobate can be represented by the formula AgNbO3.

[0032]

[0069] For purposes of illustration, and without implying any limitation, niobates generally meet IFL requirements such as piezoelectric behavior, nonlinear optical polarizability, photoelasticity, ferroelectricity, Pockels effect, sufficient charge carrier mobility, optical transparency, matching energy levels, and high dielectric constants.

[0033]

[0070] In one embodiment, perovskite material devices can be formulated by casting PbI2 onto a SrTiO3-coated ITO substrate. The PbI2 can be converted to MAPbI3 by a dipping process, which is described in more detail below. The resulting conversion of PbI2 to MAPbI3 is more complete (as observed by optical spectroscopy) compared to preparations with substrates that do not contain SrTiO3.

[0034]

[0071] The interfacial materials described herein may further include doped compositions. To modify the properties (e.g., electrical, optical, mechanical) of the interfacial material, stoichiometric or non-stoichiometric materials can be doped with one or more elements (e.g., Na, Y, Mg, N, P) in amounts ranging from 1 ppb% to 50 mol%. Some examples of interfacial materials include NiO, TiO2, SrTiO3, Al2O3, ZrO2, WO3, VO5, MO3, ZnO, graphene, and carbon black. Examples of possible dopants for these interface materials include Li, Na, Be, Mg, Ca, Sr, Ba, Sc, Y, Nb, Ti, Fe, Co, Ni, Cu, Ga, Sn, In, B, N, P, C, S, As, halides, pseudohalides (e.g., cyanide, cyanate, isocyanate, fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate, carbamoyldicyanomethanide, dicyanonitrose, dicyanamide, and tricyanomethanide), and Al in any of its oxidation states. Reference to doped interface materials herein is not intended to limit the ratio of components in the interface material compound.

[0035]

[0072] In some embodiments, multiple IFLs made from different materials can be placed adjacent to one another to form a composite IFL. This configuration may include two different IFLs, three different IFLs, or even more different IFLs. The resulting multilayer or composite IFL can be used in place of a single-material IFL. For example, a composite IFL can be any IFL shown in the example of FIG. 2 , such as IFL3903, IFL3905, IFL3907, IFL3909, or IFL3911. Although a composite IFL differs from a single-material IFL, assembling perovskite material PV cells with multilayer IFLs is not substantially different from assembling perovskite material PV cells with only single-material IFLs.

[0036]

[0073] In general, a composite IFL can be fabricated using any of the materials described herein suitable for the IFL. In one embodiment, the IFL includes a layer of Al2O3 and a layer of ZnO or M:ZnO (doped ZnO, e.g., Be:ZnO, Mg:ZnO, Ca:ZnO, Sr:ZnO, Ba:ZnO, Sc:ZnO, Y:ZnO, Nb:ZnO). In one embodiment, the IFL includes a layer of ZrO2 and a layer of ZnO or M:ZnO. In some embodiments, the IFL includes multiple layers. In some embodiments, a multilayer IFL generally includes a conductor layer, a dielectric layer, and a semiconductor layer. In some embodiments, the layers can alternate between conductor layer, dielectric layer, semiconductor layer, dielectric layer, and semiconductor layer, for example. Examples of multilayer IFLs include an IFL with an ITO layer, an Al2O3 layer, a ZnO layer, and a second Al2O3 layer; an IFL with an ITO layer, an Al2O3 layer, a ZnO layer, a second Al2O3 layer, and a second ZnO layer; an IFL with an ITO layer, an Al2O3 layer, a ZnO layer, a second Al2O3 layer, a second ZnO layer, and a third Al2O3 layer; or an IFL with as many layers as necessary to achieve desired performance characteristics. As above, reference to specific stoichiometric ratios is not intended to limit the ratios of components in IFL layers according to various embodiments.

[0037]

[0074] Arranging two or more adjacent IFLs as a composite IFL can sometimes exceed the performance of a single IFL in perovskite material PV cells where the attributes of each IFL material are utilized in a single IFL. For example, in an architecture with an ITO layer, an Al2O3 layer, and a ZnO layer, ITO is the conductive electrode, Al2O3 is the dielectric material, ZnO is an n-type semiconductor, and ZnO acts as an electron acceptor with good electron transport properties (e.g., mobility). Furthermore, Al2O3 is a physically robust material that has excellent adhesion to ITO, homogenizes the surface by capping surface defects (e.g., charge traps), and improves device diode performance by suppressing dark current.

[0038]

[0075] Additionally, some perovskite material PV cells may include so-called "tandem" PV cells, in which there are two or more perovskite photoactive layers. For example, photoactive materials 3908 and 3906 in Figure 2 may both be perovskite materials. In such tandem PV cells, the interfacial layer between the two photoactive layers, such as IFL 3907 (i.e., the recombination layer) in Figure 2, may comprise a multi-layer, or composite IFL. In some embodiments, the layer sandwiched between the two photoactive layers of a tandem PV device may comprise an electrode layer.

[0039]

[0076] A tandem PV device may include the following layers, listed in that order or in reverse order: a first substrate, a first electrode, a first interfacial layer, a first perovskite material, a second interfacial layer, a second electrode, a third interfacial layer, a second perovskite material, a fourth interfacial layer, and a third electrode. In some embodiments, the first and third interfacial layers may be hole-transporting interfacial layers, and the second and fourth interfacial layers may be electron-transporting interfacial layers. In other embodiments, the first and third interfacial layers may be electron-transporting interfacial layers, and the second and fourth interfacial layers may be hole-transporting interfacial layers. In yet other embodiments, the first and fourth interfacial layers may be hole-transporting interfacial layers, and the second and third interfacial layers may be electron-transporting interfacial layers. In other embodiments, the first and fourth interfacial layers may be electron-transporting interfacial layers, and the second and third interfacial layers may be hole-transporting interfacial layers. In a tandem PV device, the first and second perovskite materials may have different bandgaps. In some embodiments, the first perovskite material may be formamidinium lead bromide (FAPbBr3) and the second perovskite material may be formamidinium lead iodide (FAPbI3). In other embodiments, the first perovskite material may be methylammonium lead bromide (MAPbBr3) and the second perovskite material may be formamidinium lead iodide (FAPbI3). In other embodiments, the first perovskite material may be methylammonium lead bromide (MAPbBr3) and the second perovskite material may be methylammonium lead iodide (MAPbI3).

[0040]

[0077] Perovskite Materials Perovskite materials may be incorporated into one or more aspects of PV or other devices. Perovskite materials according to certain embodiments may have the general formula CwMyXz, where C comprises one or more cations (e.g., amines, ammonium, phosphonium, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds), M comprises one or more metals (examples include Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr), X comprises one or more anions, and w, y, and z represent real numbers between 1 and 20. In certain embodiments, C may comprise one or more organic cations. In certain embodiments, each organic cation C may be larger than each metal M, and each anion X may bind to both the cation C and the metal M. In some embodiments, the perovskite material may have the formula CMX3.

[0041]

[0078] In certain embodiments, C is ammonium, a group of the general formula [NR4] +where the R groups can be the same or different. Suitable R groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl groups or isomers thereof; any alkane, alkene, or alkyne CxHy, where x=1-20, y=1-42, cyclic, branched, or straight chain; alkyl halides CxHyXz, where x=1-20, y=0-42, z=1-42, and X=F, Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes containing at least one nitrogen atom in the ring (e.g., pyridine, pyrrole, pyrrolidine, piperidine, tetrahydroquinoline); any sulfur-containing group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); Examples include, but are not limited to, sulfoxides, thiols, alkyl sulfides; any nitrogen-containing group (nitroxides, amines); any phosphorus-containing group (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid) and its ester or amide derivatives; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histidine, 5-ammonium valerate), including α, β, γ and higher derivatives; any silicon-containing group (e.g., siloxane); and any alkoxy or group, —OCxHy (where x=0-20, y=1-42).

[0042]

[0079] In certain embodiments, C is formamidinium, a compound of the general formula [RNCRNR] +where the R groups are the same or different (e.g., acetic acid, propanoic acid). Suitable R groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl groups or isomers thereof; any alkane, alkene, or alkyne CxHy, where x=1-20, y=1-42, cyclic, branched, or straight chain; alkyl halides CxHyXz, where x=1-20, y=0-42, z=1-42, and X=F, Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes containing at least one nitrogen atom in the ring (e.g., imidazole, benzimidazole, (azolidinylidenemethyl)pyrrolidine, triazole); any sulfur Any nitrogen-containing group (nitroxide, amine); any phosphorus-containing group (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid) and its ester or amide derivatives; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histidine, 5-ammonium valerate), including α, β, γ and higher derivatives; any silicon-containing group (e.g., siloxane); and any alkoxy or group, -OCxHy (where x = 0-20, y = 1-42).

[0043]

[0080] [ka] Equation 1 is expressed as [R2NCRNR2] as above. + The structure of the formamidinium cation represented by the general formula: Formula 2:

[0044] [ka] shows example structures of some formamidinium cations that can function as the cation "C" in perovskite materials.

[0045]

[0081] In certain embodiments, C is guanidinium, a group of the general formula [(RN)C=NR] + where the R groups can be the same or different. Suitable R groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl groups or isomers thereof; any alkane, alkene, or alkyne CxHy (x=1-20, y=1-42, cyclic, branched, or straight chain); alkyl halides CxHyXz (where x=1-20, y=0-42, z=1-42, and X=F, Cl, Br, or I); any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes containing at least one nitrogen atom in the ring (e.g., octahydropyrimido[1,2-a]pyrimidine, pyrimido[1,2-a]pyrimidine, hexahydroimidazo[1,2-a]imidazole, hexahydroimidine-2- imines); any sulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group (nitroxide, amine); any phosphorus-containing group (phosphate); any boron-containing group (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid) and its ester or amide derivatives; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histidine, 5-ammonium valerate), including α, β, γ and higher derivatives; any silicon-containing group (e.g., siloxane); and any alkoxy or group, —OCxHy (where x=0-20, y=1-42).

[0046]

[0082] [ka] Equation 3 is expressed as [(R2N)2C=NR2] as above. + The structure of the guanidinium cation represented by the general formula: Formula 4:

[0047] [ka] shows examples of the structures of some guanidinium cations that can function as the cation "C" in perovskite materials.

[0048]

[0083] In certain embodiments, C is an ethenetetramine cation, i.e., a cation of the general formula [(RN)C=C(NR)] + where the R groups can be the same or different. Suitable R groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl groups or isomers thereof; any alkane, alkene, or alkyne CxHy (x=1-20, y=1-42, cyclic, branched, or straight chain); alkyl halides CxHyXz (where x=1-20, y=0-42, z=1-42, and X=F, Cl, Br, or I); any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes containing at least one nitrogen atom in the ring (e.g., 2-hexahydropyrimidine, octahydropyrazino[2,3-b]pyrazine, pyrazino[2,3-b]pyrazine, quinoxaline); any sulfur atom. any nitrogen-containing group (nitroxide, amine); any phosphorus-containing group (phosphate); any boron-containing group (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid) and its ester or amide derivatives; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histidine, 5-ammonium valerate), including α, β, γ and higher derivatives; any silicon-containing group (e.g., siloxane); and any alkoxy or group, —OCxHy (where x=0-20, y=1-42).

[0049]

[0084] [ka] Equation 5 is the above [(R2N)2C=C(NR2)2] + The structure of the ethenetetramine cation represented by the general formula: Formula 6:

[0050] [ka] shows examples of the structures of some ethenetetramine ions that can function as the cation "C" in perovskite materials.

[0051]

[0085] In some embodiments, C is an imidazolium cation, of the general formula [CRNRCRNRCR] + The R groups may be the same or different. Suitable R groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl groups or isomers thereof; alkanes, alkenes, or alkynes CxHy (x=1-20, y=1-42, cyclic, branched, or straight chain); alkyl halides, alkyl halides CxHyXz (where x=1-20, y=0-42, z=1-42, and X=F, Cl, Br, or I); any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); and cyclic complexes containing at least one nitrogen atom in the ring (e.g., 2-hexahydropyrimidine, octahydropyrazino[2,3-b]pyrazine, pyrazino[2,3-b]pyrazine, quinoxaline[2,3-b]quinoxaline). any sulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group (nitroxide, amine); any phosphorus-containing group (phosphate); any boron-containing group (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid) and its ester or amide derivatives; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histidine, 5-ammonium valerate), including α, β, γ and higher derivatives; any silicon-containing group (e.g., siloxane); and any alkoxy or group, —OCxHy (where x=0-20, y=1-42).

[0052]

[0086] In certain embodiments, C is a pyridinium cation, of the general formula [CRCRCRCRNR] +The R groups may be the same or different. Suitable R groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl groups or isomers thereof; alkanes, alkenes, or alkynes CxHy (x=1-20, y=1-42, cyclic, branched, or straight chain); alkyl halides, alkyl halides CxHyXz (where x=1-20, y=0-42, z=1-42, and X=F, Cl, Br, or I); any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); and cyclic complexes containing at least one nitrogen atom in the ring (e.g., 2-hexahydropyrimidine, octahydropyrazino[2,3-b]pyrazine, pyrazino[2,3-b]pyrazine, quinoxaline[2,3-b]quinoxaline). any sulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group (nitroxide, amine); any phosphorus-containing group (phosphate); any boron-containing group (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid) and its ester or amide derivatives; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histidine, 5-ammonium valerate), including α, β, γ and higher derivatives; any silicon-containing group (e.g., siloxane); and any alkoxy or group, —OCxHy (where x=0-20, y=1-42).

[0053] [ka]

[0087] In some embodiments, X may comprise one or more halides. In some embodiments, X may alternatively or instead comprise a Group 16 anion. In some embodiments, the Group 16 anion may be an oxide, sulfide, selenide, or telluride. In some embodiments, X may alternatively or instead comprise one or more pseudohalides (e.g., cyanide, cyanate, isocyanate, fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate, carbamoyldicyanomethanide, dicyanonitrose, dicyanamide, and tricyanomethanide).

[0054]

[0088] In one embodiment, the perovskite material may comprise an empirical formula CMX3, where C comprises one or more of the above cations, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds; M comprises one or more metals (examples include Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr); and X comprises one or more of the above anions.

[0055]

[0089] In another embodiment, the perovskite material may have the empirical formula C'M2X6, where C' is a 2-component compound comprising one or more of the above cations, diammonium butane, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds. + The compounds include cations carrying a charge, where M includes one or more metals (examples include Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr), and X includes one or more of the above anions.

[0056]

[0090] In another embodiment, the perovskite material may have the empirical formula C'MX4, where C' is a 2-component compound comprising one or more of the above cations, diammonium butane, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds. +In some embodiments, the perovskite material may comprise a charged cation, where M comprises one or more metals (e.g., examples include Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr), and X comprises one or more of the above anions. In such embodiments, the perovskite material may have a two-dimensional structure.

[0057]

[0091] In one embodiment, the perovskite material may have an empirical formula of C3M2X9, where C includes one or more of the above cations, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds; M includes one or more metals (e.g., examples include Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr); and X includes one or more of the above anions.

[0058]

[0092] In one embodiment, the perovskite material can have an empirical formula of CM2X7, where C includes one or more of the above cations, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds; M includes one or more metals (including, by way of example, Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zrn); and X includes one or more of the above anions.

[0059]

[0093] In one embodiment, the perovskite material may comprise an empirical formula C2MX4, where C comprises one or more of the above cations, Group 1 metals, Group 2 metals, and / or other cations or cation-like compounds; M comprises one or more metals (with examples including Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr); and X comprises one or more of the above anions.

[0060]

[0094] Perovskite materials also include mixed ion formulations where C, M, or X contain more than one species, e.g., Cs 0.1 FA 0.9 Pb(I 0.9 Cl 0.1 )3;Rb 0.1 FA 0.9 Pb(I 0.9 Cl 0.1 )3Cs 0.1 FA 0.9 PbI3;FAPb 0.5 Sn 0.5 I3;FA 0.83 Cs 0.17 Pb(I 0.6 Br 0.4 )3;FA 0.83 Cs 0.12 Rb 0.05 Pb(I 0.6 Br 0.4 )3 and FA 0.85 MA 0.15 Pb(I 0.85 Br 0.15 )3.

[0061]

[0095] Composite perovskite material device design In certain embodiments, the present disclosure may provide hybrid designs for PV and other similar devices (e.g., batteries, hybrid PV cells, FETs, LEDs, nonlinear optical systems (NLO), waveguides, etc.) that include one or more perovskite materials. For example, one or more perovskite materials may function as either or both of the first and second active materials of certain embodiments (e.g., active materials 3906a and 3908a in FIG. 3 ). More generally, certain embodiments of the present disclosure provide PV or other devices having an active layer that includes one or more perovskite materials. In such embodiments, perovskite materials (i.e., materials that include any one or more perovskite materials) may be used in the active layer in a variety of architectures. Furthermore, perovskite materials may function as any one or more components of the active layer (e.g., charge transport materials, mesoporous materials, photoactive materials, and / or interface materials), each of which is described in more detail below. In some embodiments, the same perovskite material can perform multiple such functions, while in other embodiments, multiple perovskite materials can be included in a device, with each perovskite material performing one or more of the above functions. In some embodiments, whatever function a perovskite material performs, it can be prepared and / or present in the device in a variety of states. For example, in some embodiments, it can be substantially solid. A solution or suspension can be coated or otherwise deposited within the device (e.g., onto another component of the device, such as a mesoporous layer, an interfacial layer, a charge transport layer, a photoactive layer, or other layer, and / or onto an electrode). In some embodiments, the perovskite material can be formed in situ on the surface of another component of the device (e.g., by vapor deposition as a thin film solid). Any other suitable means of forming a layer comprising a perovskite material can be used.

[0062]

[0096] Generally, a perovskite material device can include a first electrode, a second electrode, and an active layer comprising a perovskite material, with the active layer at least partially disposed between the first electrode and the second electrode. In some embodiments, the first electrode can be one of an anode and a cathode, and the second electrode can be the other of an anode and a cathode. The active layer according to some embodiments can include any one or more active layer components, including any one or more of a charge transport material, a liquid electrolyte, a mesoporous material, a photoactive material (e.g., dye, silicon, cadmium telluride, cadmium sulfide, cadmium selenide, copper indium gallium selenide, gallium arsenide, germanium indium phosphide, a semiconducting polymer, or other photoactive material), and an interface material. One or more of these active layer components can include one or more perovskite materials. In some embodiments, some or all of the active layer components can be disposed, in whole or in part, as sublayers. For example, an active layer may include one or more of an interfacial layer including an interfacial material, a mesoporous layer including a mesoporous material, and a charge transport layer including a charge transport material. Furthermore, an interfacial layer may, in some embodiments, be included between any two or more other layers of the active layer and / or between an active layer component and an electrode. References herein to layers may refer to the final arrangement (e.g., substantially discrete portions of each material separately definable within the device) and / or the arrangement during construction of the device, even though the materials in each layer may subsequently be intermixed. In some embodiments, layers may include discrete, substantially contiguous materials (e.g., layers may be as stylistically shown in FIG. 2).

[0063]

[0097] In some embodiments, the perovskite material device may be a field effect transistor (FET). The FET perovskite material device may include a source electrode, a drain electrode, a gate electrode, a dielectric layer, and a semiconducting layer. In some embodiments, the semiconducting layer of the FET perovskite material device may be a perovskite material.

[0064]

[0098] Perovskite material devices according to certain embodiments may optionally include one or more substrates. In certain embodiments, either or both of the first and second electrodes may be coated or otherwise disposed on a substrate such that the electrodes are substantially disposed between the substrate and the active layer. Materials of the device composition (e.g., substrate, electrode, active layer, and / or active layer components), in whole or in part, may be either rigid or flexible in various embodiments. In some embodiments, the electrodes function as the substrate, thereby eliminating the need for a separate substrate.

[0065]

[0099] Furthermore, perovskite material devices according to certain embodiments may optionally include an anti-reflective layer or coating. Further, perovskite material devices may include any one or more of the additives described above with respect to certain embodiments of the present disclosure.

[0066]

[0100] Some description of various materials that may be included in a perovskite material device will be made in part with reference to FIG. 2 , which is a stylized diagram of a perovskite material device 3900 according to an embodiment. While various components of device 3900 are depicted as discrete layers comprising adjacent materials, it should be understood that FIG. 2 is a stylized diagram, and thus embodiments accordingly may include such discrete layers and / or substantially intermixed, non-adjacent layers, consistent with the use of “layer” hereinabove. Device 3900 includes first and second substrates 3901 and 3913. A first electrode 3902 is disposed on the inner surface of first substrate 3901, and a second electrode 3912 is disposed on the inner surface of second substrate 3913. An active layer 3950 is sandwiched between the two electrodes 3902 and 3912. Active layer 3950 includes mesoporous layer 3904, first and second photoactive materials 3906 and 3908, charge transport layer 3910, and an interfacial layer. Additionally, Figure 2 illustrates an exemplary device 3900 according to an embodiment in which sublayers of active layer 3950 are separated by interfacial layers, with an interfacial layer disposed on each electrode 3902 and 3912. In particular, second, third, and fourth interfacial layers 3905, 3907, and 3909 are disposed between mesoporous layer 3904, first photoactive material 3906, second photoactive material 3908, and charge transport layer 3910, respectively. First and fifth interfacial layers 3903 and 3911 are disposed between (i) first electrode 3902 and mesoporous layer 3904, and (ii) charge transport layer 3910 and second electrode 3912, respectively. 2 can be characterized as substrate-electrode-active layer-electrode-substrate. The architecture of the active layer 3950 can be characterized as interfacial layer-mesoporous layer-interfacial layer-photoactive material-interfacial layer-photoactive material-interfacial layer-charge transport layer-interfacial layer. As noted above, in some embodiments, no interfacial layer need be present, or one or more interfacial layers may be included only between certain, but not all, active layer components and / or device components.

[0067]

[0101] Substrates, such as either or both of the first and second substrates 3901 and 3913, can be either rigid or flexible. If two substrates are included, at least one should be transparent or semi-transparent to electromagnetic (EM) radiation (e.g., ultraviolet, visible, or infrared). If one substrate is included, a portion of the device may, but need not, be transparent or semi-transparent as well, so long as EM radiation can contact the active layer 3950. Suitable substrate materials include one or more of glass, sapphire, magnesium oxide (MgO), mica, polymers (e.g., PEN, PET, PEG, polyolefin, polypropylene, polyethylene, polycarbonate, PMMA, polyamide, vinyl, Kapton), ceramics, carbon, composites (e.g., fiberglass, Kevlar, carbon fiber), fabrics (e.g., cotton, nylon, silk, wool), wood, drywall, tile (e.g., ceramic, composite, or clay), metal, steel, silver, gold, aluminum, magnesium, concrete, and combinations thereof.

[0068]

[0102] As noted above, an electrode (e.g., one of electrodes 3902 and 3912 in FIG. 2 ) can be either an anode or an anode. In some embodiments, one electrode can function as a cathode and the other electrode can function as an anode. One or both of electrodes 3902 and 3912 can be coupled to leads, cables, wires, or other means that allow charge transport to and / or from device 3900. The electrodes can comprise any conductive material, and at least one electrode should be transparent or semi-transparent to EM radiation and / or positioned to allow EM radiation to contact at least a portion of active layer 3950. Suitable electrode materials may include any one or more of indium tin oxide or tin-doped indium oxide (ITO); fluorine-doped tin oxide (FTO); cadmium oxide (CdO); zinc indium tin oxide (ZITO); aluminum zinc oxide (AZO); aluminum (Al); gold (Au); silver (Ag); calcium (Ca); chromium (Cr); copper (Cu); magnesium (Mg); titanium (Ti); steel; carbon (and their allotropes); doped carbon (e.g., nitrogen-doped); core-shell structured (e.g., silicon-carbon core-shell structured) nanoparticles; and combinations thereof.

[0069]

[0103] The mesoporous material (e.g., the material included in mesoporous layer 3904 of FIG. 2) can include any pore-containing material. In some embodiments, the pore diameter can range from about 1 to about 100 nm, and in other embodiments, the pore diameter can range from about 2 to about 50 nm. Suitable mesoporous materials include any interfacial material and / or mesoporous material described elsewhere herein; aluminum (Al); bismuth (Bi); cerium (Ce); hafnium (Hf); indium (In); molybdenum (Mo); niobium (Nb); nickel (Ni); silicon (Si); titanium (Ti); vanadium (V); zinc (Zn); zirconium (Zr); any one or more oxides of the foregoing metals (e.g., alumina, ceria, titania, zinc oxide, zirconia, etc.); any one or more sulfides of the foregoing metals; any one or more nitrides of the foregoing metals; and any combination thereof. In some embodiments, any material disclosed herein as an IFL can be a mesoporous material. In other embodiments, the device shown in Figure 2 may not include a mesoporous material layer, but may include only a non-mesoporous thin film or "compact" IFL.

[0070]

[0104] The photoactive material (e.g., first or second photoactive material 3906 or 3908 in FIG. 2) can be silicon (e.g., polycrystalline silicon, single crystalline silicon, or amorphous silicon), cadmium telluride, cadmium sulfide, cadmium selenide, copper indium gallium selenide, copper indium selenide, copper zinc tin sulfide, gallium arsenide, germanium, germanium indium phosphide, indium phosphide, one or more semiconducting polymers (e.g., polythiophene) (e.g., 3-hexylthiophene) and its derivatives, or P3HT; polyheptadecanylcarbazoledithienylbenzothiazolinone; The photoactive compound may include any one or more of the following: carbazole-based copolymers such as diazole and its derivatives (e.g., PCDTBT); other polymers such as polycyclopentadithiophenebenzothiadiazole and its derivatives (e.g., PCPDTBT) and polybenzodithiophenylthienothiophenediyl and its derivatives (e.g., PTB6, PTB7, PTB7-th, PCE-10); poly(triarylamine) compounds and their derivatives; polyphenylenevinylene and its derivatives (e.g., MDMO-PPV, MEH-PPV), and combinations thereof.

[0071]

[0105] In some embodiments, the photoactive material may alternatively or additionally include a dye (e.g., N719, N3, other ruthenium-based dyes). In some embodiments, a dye (of any composition) may be coated onto another layer (e.g., a mesoporous layer and / or an interfacial layer). In some embodiments, the photoactive material may include one or more perovskite materials. The perovskite-containing photoactive material may be a solid, or in some embodiments, may be in the form of a dye-containing suspension or solution containing the perovskite material. The solution or suspension may be coated onto other device components in a similar manner as other dyes. In some embodiments, the solid perovskite-containing material may be deposited by any suitable means (e.g., vapor deposition, solution deposition, direct deposition of solid materials). Devices according to various embodiments may include one, two, three, or more photoactive compounds (e.g., one, two, three, or more perovskite materials, dyes, or combinations thereof). In some embodiments that include multiple dyes or other photoactive materials, each of the two or more dyes or other photoactive materials may be separated by one or more interfacial layers. In some embodiments, the multiple dyes and / or photoactive compounds may be at least partially intermixed.

[0072]

[0106] The charge transport material (e.g., the charge transport material of charge transport layer 3910 in FIG. 2) may comprise a solid charge transport material (i.e., a so-called solid electrolyte), or may comprise a liquid electrolyte and / or an ionic liquid. Liquid electrolytes, ionic liquids, and solid charge transport materials may all be referred to as charge transport materials. As used herein, "charge transport material" refers to any material, solid, liquid, or otherwise, that can collect and / or transport charge carriers. For example, in a PV device according to certain embodiments, the charge transport material can transport charge carriers to an electrode. The charge carriers may include holes (due to which transport the charge transport material may justifiably be labeled a "hole transport material") and electrons. Holes are transported toward the anode and electrons toward the cathode, depending on the placement of the charge transport material relative to either the cathode or anode of the PV or other device. Suitable examples of charge transport materials according to certain embodiments include perovskite materials; I- / I3 - Co complexes; polythiophenes (e.g., poly(3-hexylthiophene) and its derivatives, or P3HT); carbazole-based copolymers such as polyheptadecanylcarbazoledithienylbenzothiadiazole and its derivatives (e.g., PCDTBT); polycyclopentadithiophenebenzothiadiazole and its derivatives (e.g., PCTBPDT), polybenzodithiophenylthienothiophenediyl and its derivatives (e.g., PTB6, PTB7, PTB7-th, PCE-10); poly(triarylamine) compounds and their derivatives (e.g., PTAA); spiro-OMeTAD; polyphenylenevinylene and its derivatives (e.g., MDMO-PV, MEH-PV); fullerenes and / or fullerene derivatives (e.g., C60, PCBM); carbon nanotubes; graphite; graphene; carbon black; amorphous carbon; glassy carbon; carbon fibers; and combinations thereof. In some embodiments, the charge transport material may comprise any solid or liquid material capable of collecting charge carriers (electrons or holes) and / or transporting charge carriers. Thus, in some embodiments, the charge transport material may be an n-type or p-type active, ambipolar, and / or intrinsic semiconductor material. The charge transport material may be disposed adjacent to one of the electrodes of the device. In some embodiments, it may be disposed adjacent to the electrode, while in other embodiments, an interfacial layer may be disposed between the charge transport material and the electrode (e.g., as shown in FIG. 2 , with fifth interfacial layer 3911). In some embodiments, the type of charge transport material may be selected based on the electrode to which it is adjacent. For example, if the charge transport material collects and / or transports holes, it may be disposed adjacent to the anode so as to transport holes to the anode. However, the charge transport material may instead be disposed adjacent to the cathode and selected or configured to transport electrons to the cathode.

[0073]

[0107] As noted above, devices according to various embodiments may optionally include an interfacial layer between any two other layers and / or materials, while devices according to certain embodiments may not include any interfacial layers. Thus, for example, a perovskite material device may include zero, one, two, three, four, five, or more interfacial layers (e.g., the exemplary device of FIG. 2 includes five interfacial layers 3903, 3905, 3907, 3909, and 3911). The interfacial layers may include thin-film interfacial layers according to previous embodiments herein (e.g., including alumina and / or other metal oxide particles, and / or titanium oxide / metal oxide bilayers, and / or other compounds according to the thin-film interfacial layers described elsewhere herein). Interfacial layers according to certain embodiments may include any suitable material for enhancing charge transport and / or collection between two layers or materials, helping to prevent or reduce the likelihood of charge recombination after charge is transferred from one of the materials adjacent to the interfacial layer.Suitable interfacial materials include any of the mesoporous materials and / or interfacial materials described elsewhere herein; Ag, Al, Au, B, Bi, Ca, Cd, Ce, Co, Cu, Fe, Ga, Ge, H, In, Mg, Mn, Mo, Nb, Ni, Pt, Sb, Sc, Si, Sn, Ta, Ti, V, W, Y, Zn, Zr, carbides of any of the foregoing metals (e.g., SiC, FeC, WC); carbides of any of the foregoing metals (e.g., MgSi, SrSi, SnSi); oxides of any of the foregoing metals (e.g., alumina, silica , titania, SnO2, ZnO; sulfides of any of the above metals (e.g., CdS, MoS2, SnS2); nitrides of any of the above metals (e.g., Mg3N2, TiN, BN, Si3N4); selenides of any of the above metals (e.g., CdSe, FeSe2, ZnSe), tellurides of any of the above metals (e.g., CdTe, TiTe2, ZnTe), phosphides of any of the above metals (e.g., InP, GaP), arsenides of any of the above metals (e.g., CoAs3, GaAs, InGaAs, NiAs), antimonides of any of the foregoing metals (e.g., AlSb, GaSb, InSb), halides of any of the foregoing metals (e.g., CuCl), CuI, BiI3; pseudohalides of any of the foregoing metals (e.g., CuSCN, AuCN2); carbonates of any of the foregoing metals (e.g., CaCO3, Ce2(CO3)3); functionalized or non-functionalized alkylsilyl groups; graphite; graphene; fullerenes; carbon nanotubes; any mesoporous and / or interfacial materials described elsewhere herein; and combinations thereof. Examples of interfacial layers include one or more of any of a combination of layers (including, in some embodiments, bilayers, trilayers, or multilayers of composite materials). In some examples, the interfacial layer may include a perovskite material. Additionally, the interfacial layer may include doped embodiments of any of the interfacial materials described herein (e.g., Y-doped ZnO, N-doped single-walled carbon nanotubes). The interfacial layer may also include a compound comprising three of the above materials (e.g., CuTiO3, Zn2SnO4) or a compound comprising four of the above materials (e.g., CoNiZnO).

[0074]

[0108] As an example, Figure 3 illustrates an embodiment of a perovskite material device 3900a having a structure similar to the perovskite material device 3900 shown in Figure 2. Figure 3 is a stylized diagram of the perovskite material device 3900a according to certain embodiments. While various components of device 3900a are depicted as discrete layers comprising adjacent materials, it should be understood that Figure 3 is a stylized diagram. Accordingly, embodiments therewith may include such discrete layers and / or substantially intermixed non-adjacent layers, consistent with the use of "layer" herein above. Figure 3 includes active layers 3906a and 3908a. In certain embodiments, one or both of active layers 3906a and 3908a may include any perovskite photoactive material described above with respect to Figure 2. In other embodiments, one or both of active layers 3906a and 3908a may include any photoactive material described herein, such as thin-film semiconductors (e.g., CdTe, CZTS, CIGS), photoactive polymers, dye-sensitized photoactive materials, fullerenes, small molecule photoactive materials, and crystalline and polycrystalline semiconductor materials (e.g., silicon, GaAs, InP, Ge). In still other embodiments, one or both of active layers 3906a and 3908a may include a light-emitting diode (LED), a field-effect transistor (FET), a thin-film cell layer, or a combination thereof. In small molecule photoactive material embodiments, one of active layers 3906a and 3908a may include a photoactive material, and the other may include a light-emitting diode (LED), a field-effect transistor (FET), a thin-film cell layer, or a combination thereof. For example, active layer 3908a may include a perovskite material photoactive layer, and active layer 3906b may include a field-effect transistor layer. Other layers shown in FIG. 3, such as layers 3901a, 3902a, 3903a, 3904a, 3905a, 3907a (i.e., recombination layer), 3909a, 3910a, 3911a, 3912a, and 3913a, may be similar to the corresponding layers as described herein with respect to FIG. 2.

[0075]

[0109] Furthermore, in some embodiments, a perovskite material may have more than two active layers. As an example, FIG. 4 illustrates an embodiment of a perovskite material device 3900b having a structure similar to the perovskite material device 3900 shown in FIG. 2. FIG. 3 is a stylized diagram of perovskite material device 3900b according to some embodiments. While various components of device 3900b are depicted as discrete layers comprising adjacent materials, it should be understood that FIG. 4 is a stylized diagram. Accordingly, embodiments therewith may include such discrete layers and / or substantially intermixed non-adjacent layers, consistent with the use of "layer" hereinabove. FIG. 4 includes active layers 3904b, 3906b, and 3908b. In some embodiments, one or more of active layers 3904b, 3906b, and 3908b may include any perovskite photoactive material described above with respect to FIG. 2. In other embodiments, one or more of active layers 3904b, 3906b, and 3908b may include any photoactive material described herein, such as thin-film semiconductors (e.g., CdTe, CZTS, CIGS), photoactive polymers, dye-sensitized photoactive materials, fullerenes, small molecule photoactive materials, and crystalline and polycrystalline semiconductor materials (e.g., silicon, GaAs, InP, Ge). In still other embodiments, one or more of active layers 3904b, 3906b, and 3908b may include a light-emitting diode (LED), a field-effect transistor (FET), a thin-film battery layer, or a combination thereof. In embodiments, one or more of the active layers of active layers 3904b, 3906b, and 3908b may include a photoactive material, and the other may include a light-emitting diode (LED), a field-effect transistor (FET), a thin-film battery layer, or a combination thereof. For example, active layers 3908a and 3906b may both include perovskite material photoactive layers, and active layer 3904b may include a field effect transistor layer. Other layers shown in Figure 3, such as layers 3901b, 3902b, 3903b, 3904b, 3905b (i.e., recombination layer), 3907b (i.e., recombination layer), 3909b, 3910b, 3911b, 3912b, and 3913b, may be similar to the corresponding layers as described herein with respect to Figure 2.

[0076]

[0110] Further, more specific exemplary embodiments of perovskite devices will be described with reference to further stylized depictions of exemplary devices. The stylized nature of these depictions, Figures 1-4, likewise, is not intended to limit the types of devices that may, in some embodiments, be configured according to any one or more of the architectures of Figures 1-4. Figures 1-4 can be adapted to provide other embodiments of BHJs, batteries, FETs, hybrid PV batteries, serial multi-cell PVs, parallel multi-cell PVs, and other similar devices of the present disclosure according to any suitable means, including both those explicitly described elsewhere herein and other suitable means that would be apparent to one of ordinary skill in the art having the benefit of this disclosure.

[0077]

[0111] Formation of perovskite material active layer As noted above, in some embodiments the perovskite material in the active layer is CMX 3-y X' y (0≧y≧3), where C comprises one or more cations (e.g., amines, ammonium, Group 1 metals, Group 2 metals, formamidinium, guanidinium, tetramine, phosphonium, imidazolium, and / or other cations or cation-like compounds), M comprises one or more metals (e.g., Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr), and X and X′ comprise one or more anions. In one embodiment, the perovskite material is CPbI 3-y Cl y In some embodiments, the perovskite material may be deposited as an active layer onto a substrate layer using the process described below, for example by drop casting, spin casting, slot die printing, screen printing, or inkjet printing.

[0078]

[0112] First, a lead halide precursor ink is formed. A quantity of lead halide can be masked in a clean, dry container in a controlled atmosphere environment (e.g., a controlled atmosphere box with a porthole containing gloves allows for manipulation of the material in an airless environment). Suitable lead halides include, but are not limited to, lead(II) iodide, lead(II) bromide, lead(II) chloride, and lead(II) fluoride. The lead halide may consist of a single lead halide species or a mixture of lead halides in precise ratios. In some embodiments, the lead halide mixture may consist of any binary, ternary, or quaternary ratio of 0.001 to 100 mole percent iodide, bromide, chloride, or fluoride. In one embodiment, the lead halide mixture may include lead(II) chloride and lead(II) iodide in a mole:mol ratio of about 10:90. In other embodiments, the lead halide mixture may include lead(II) chloride and lead(II) iodide in a ratio of about 5:95, about 7.5:92.5, or about 15:85 mole:molar.

[0079]

[0113] Alternatively, other lead salt precursors can be used in conjunction with or in place of the lead halide salts to form the precursor ink. Suitable precursor salts may include lead(II) or lead(IV) in combination with any of the following anions: nitrate, nitrite, carboxylate, acetate, acetonylacetonate, formate, oxalate, sulfate, sulfite, thiosulfate, phosphate, tetrafluoroborate, hexafluorophosphate, tetra(perfluorophenyl)borate, hydride, oxide, peroxide, hydroxide, arsenate, arsenite, perchlorate, carbonate, bicarbonate, chromate, dichromate, iodate, bromate, chlorate, chlorite, hypochlorite, hypobromite, cyanide, cyanate, isocyanate, fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate, carbamoyldicyanomethanide, dicyanonitrosethanide, dicyanamide and tricyanomethanide, tricyanomethanide, amide, and permanganate.

[0080]

[0114] The precursor ink may further contain, as a salt of the anion, a lead(II) salt or a lead(IV) salt in a molar ratio of 0 to 100% relative to the following metal ions: Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr.

[0081]

[0115] A solvent can then be added to the container to dissolve the lead solids and form the lead halide precursor ink. Suitable solvents include, but are not limited to, dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethyl sulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof. In one embodiment, the lead solids are dissolved in dry dimethylformamide (DMF). The lead solids can be dissolved at a temperature of about 20-150°C. In one embodiment, the lead solids dissolve at about 85°C and can be dissolved as needed to form a solution, which can occur for up to about 72 hours. The resulting solution forms the base of the lead halide precursor ink. In an embodiment, the lead halide concentration of the lead halide precursor ink may be from about 0.001 M to about 10 M. In one embodiment, the lead halide concentration of the lead halide precursor ink may be about 1 M.

[0082]

[0116] In some cases, certain additives can be added to the lead halide precursor ink to affect the final perovskite crystallinity and stability. In some embodiments, the lead halide precursor ink may further include an amino acid (e.g., 5-aminovaleric acid, histidine, glycine, lysine), an amino acid hydrogen halide (e.g., 5-aminovaleric acid hydrochloride), an IFL surface modification (SAM) agent (e.g., those described hereinabove), or a combination thereof. Suitable amino acids for the lead halide precursor ink include, but are not limited to, α-amino acids, β-amino acids, γ-amino acids, δ-amino acids, and any combination thereof. In one embodiment, formamidinium chloride may be added to the lead halide precursor ink. In other embodiments, halides of any of the cations described hereinabove may be used. In some embodiments, a combination of additives may be added to the lead halide precursor ink, including, for example, a combination of formamidinium chloride and 5-aminovaleric acid chloride.

[0083]

[0117] For illustrative purposes, and without limiting the present disclosure to any particular theory of mechanism, formamidinium chloride and 5-aminovaleric acid have been found to improve the stability of perovskite PV devices when used as additives or countercations in the one-step fabrication of perovskite devices. It has also been found that adding chloride, in the form of PbCl, to a PbI precursor solution can improve the performance of a two-step perovskite PV device. It has been found that a two-step perovskite thin film deposition process can be improved by adding formamidinium chloride and / or 5-aminovaleric acid hydrochloride directly to a lead halide precursor solution (e.g., PbI), thereby utilizing the benefits of both materials in a single material. Other perovskite film formation processes can similarly be improved by adding formamidinium chloride, 5-aminovaleric acid chloride, or PbCl to a lead halide precursor solution.

[0084]

[0118] An additive comprising formamidinium chloride and / or 5-aminovaleric acid hydrochloride can be added to the lead halide precursor ink at various concentrations depending on the desired properties of the resulting perovskite material. In one embodiment, the additive can be added at a concentration of about 1 nM to about 1 M. In another embodiment, the additive can be added at a concentration of about 1 μM to about 1 M. In another embodiment, the additive can be added at a concentration of about 1 μM to about 1 mM.

[0085]

[0119] Optionally, in some embodiments, water may be added to the lead halide precursor ink. For illustrative purposes, and without limiting the disclosure to a particular theory or mechanism, the presence of water affects perovskite thin film crystal growth. Under normal circumstances, water is absorbed as vapor from the air. However, by adding water directly to the lead halide precursor ink at specific concentrations, the crystallinity of the perovskite PV can be controlled. Suitable water includes distilled water, deionized water, or other water sources that are substantially free of contaminants (including minerals). Based on optical IV sweeps, the light-to-electrical power conversion efficiency of perovskite PVs has been found to be nearly tripled with the addition of water compared to completely dry devices.

[0086]

[0120] Water can be added to the lead halide precursor ink at various concentrations depending on the desired properties of the resulting perovskite material. In one embodiment, water may be added at a concentration of about 1 nL / mL to about 1 mL / mL. In another embodiment, water may be added at a concentration of about 1 μL / mL to about 0.1 mL / mL. In another embodiment, water may be added at a concentration of about 1 μL / mL to about 20 μL / mL.

[0087]

[0121] The lead halide precursor ink can then be deposited onto a desired substrate. Suitable substrate layers can include any of the substrate layers described above in this disclosure. As noted above, the lead halide precursor ink can be deposited via a variety of means, including, but not limited to, drop casting, spin casting, slot die printing, screen printing, or inkjet printing. In some embodiments, the lead halide precursor ink can be spin-coated onto the substrate at a speed of about 500 rpm to about 10,000 rpm for a period of about 5 seconds to about 600 seconds. In one embodiment, the lead halide precursor ink can be spin-coated onto the substrate at about 3000 rpm for about 30 seconds. The lead halide precursor ink can be deposited onto the substrate in an ambient atmosphere at a humidity range of about 0% relative humidity to about 50% relative humidity. The lead halide precursor ink can then be dried in a substantially water-free atmosphere, i.e., an atmosphere with a relative humidity of less than 30%, to form a thin film.

[0088]

[0122] The thin film can then be thermally annealed at a temperature of about 20°C to about 300°C for a period of up to about 24 hours. In one embodiment, the thin film can be thermally annealed at a temperature of about 50°C for about 10 minutes. The perovskite material active layer can then be completed by a conversion process in which the precursor film is immersed or rinsed in a solution containing a solvent or mixture of solvents (e.g., DMF, isopropanol, methanol, ethanol, butanol, chloroform, chlorobenzene, dimethyl sulfoxide (DMSO), water) and a salt (e.g., formamidinium iodide, guanidinium iodide, 1,2,2-triaminovinylammonium, 5-aminovaleric acid hydrochloride) at a concentration of 0.001M to 10M. In some embodiments, the thin film can also be thermally post-annealed in the same manner as in the first line of this paragraph.

[0089]

[0123] In some embodiments, the lead salt precursor can be deposited on a substrate to form a lead salt thin film. The temperature of the substrate can be approximately equal to ambient temperature or can be controlled between 0°C and 500°C. The lead salt precursor can be deposited by various methods known in the art, including, but not limited to, spin coating, slot-die printing, inkjet printing, gravure printing, screen printing, sputtering, PE-CVD, thermal evaporation, and spray coating. In some embodiments, deposition of the lead salt precursor can include sheet-to-sheet or roll-to-roll manufacturing methods. Deposition of the lead salt precursor can be performed in various atmospheres, such as atmospheric pressure (e.g., about 1 atm, depending on altitude and atmospheric conditions) or subatmospheric pressure (e.g., 1 mTorr to 500 mTorr). The deposition atmosphere can be ambient air, a controlled humidity environment (e.g., 0-100 g HO / m of gas), or a controlled humidity environment (e.g., 0-100 g HO / m of gas). 3 ), pure argon, pure nitrogen, pure oxygen, pure hydrogen, pure helium, pure neon, pure krypton, pure CO2, or any combination of the above gases. A controlled humidity environment may include an environment in which the absolute humidity or % relative humidity is held at a fixed value, or an environment in which the absolute humidity or % relative humidity is varied according to a predetermined set point or function. In some embodiments, deposition may occur in a controlled humidity environment in which the relative humidity is between 0% and 50%. In other embodiments, deposition may occur in a controlled humidity environment in which the relative humidity is between 0% and 50%. 3 More than 20g H2O / m 3 This can be done in a controlled humidity environment containing the following gases:

[0090]

[0124] The lead salt precursor may be a liquid, gas, solid, or a combination of these states, such as a solution, suspension, colloid, foam, gel, or aerosol. In some embodiments, the lead salt precursor may be a solution containing one or more solvents. For example, the lead salt precursor may contain one or more of N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethyl sulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof. The lead salt precursor may include a single lead salt (e.g., lead(II) iodide, lead(II) thiocyanate) or any combination of those disclosed herein (e.g., PbI2 + PbCl2; PbI2 + Pb(SCN)2). The lead salt precursor may also contain one or more additives, such as an amino acid (e.g., 5-aminovaleric acid hydroiodide), 1,8-diiodooctane, 1,8-dithiooctane, formamidinium halide, acetic acid, trifluoroacetic acid, methylammonium halide, or water. The lead halide precursor ink can be dried in a substantially water-free atmosphere, i.e., an atmosphere with a relative humidity of less than 30%, to form a thin film. The thin film can then be thermally annealed at temperatures between about 20°C and about 300°C for a period of up to about 24 hours. Thermal annealing can be performed in a variety of atmospheres, including atmospheric pressure (e.g., about 1 atmosphere, depending on altitude and atmospheric conditions) or subatmospheric pressure (e.g., 1 mTorr to 500 mTorr). The annealing atmosphere can be ambient air, a controlled humidity environment (e.g., 0 to 100 g HO / m of gas), or a controlled humidity environment (e.g., 0 to 100 g HO / m of gas). 3The controlled humidity environment may include an environment in which the absolute humidity or % relative humidity is held at a fixed value, or an environment in which the absolute humidity or % relative humidity is varied according to a predetermined set point or function. In some embodiments, annealing may occur in a controlled humidity environment with a relative humidity between 0% and 50%. In other embodiments, annealing may occur in a controlled humidity environment with a relative humidity of 0 g HO / m 3 More than 20g H2O / m 3 This can be done in a controlled humidity environment containing the following gases:

[0091]

[0125] After the lead salt precursor is deposited, a second salt precursor (e.g., formamidinium iodide, formamidinium thiocyanate, guanidinium thiocyanate) can be deposited on the lead salt thin film, which can be at approximately ambient temperature or at a controlled temperature between 0°C and 500°C. In some embodiments, the second salt precursor can be deposited at ambient temperature or at an elevated temperature between about 25°C and 125°C. The second salt precursor can be deposited by various methods known in the art, including, but not limited to, spin coating, slot-die printing, inkjet printing, gravure printing, screen printing, sputtering, PE-CVD, thermal evaporation, and spray coating. Deposition of the second salt precursor can be carried out in various atmospheres, at atmospheric pressure (e.g., about 1 atmosphere, depending on altitude and atmospheric conditions) or subatmospheric pressure (e.g., 1 mTorr to 500 mTorr). The deposition atmosphere can be ambient air, a controlled humidity environment (e.g., 0–100 g HO / m of gas), or 3), pure argon, pure nitrogen, pure oxygen, pure hydrogen, pure helium, pure neon, pure krypton, pure CO2, or any combination of the above gases. A controlled humidity environment may include an environment in which the absolute humidity or % relative humidity is held at a fixed value, or an environment in which the absolute humidity or % relative humidity is varied according to a predetermined set point or function. In some embodiments, deposition may occur in a controlled humidity environment in which the relative humidity is between 0% and 50%. In other embodiments, deposition may occur in a controlled humidity environment in which the relative humidity is between 0% and 50%. 3 More than 20g H2O / m 3 This can be done in a controlled humidity environment containing the following gases:

[0092]

[0126] In some embodiments, the second salt precursor can be a solution containing one or more solvents. For example, the second salt precursor can contain one or more of dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethylsulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof.

[0093]

[0127] After deposition of the lead salt precursor and the second salt precursor, the substrate can be annealed. Annealing the substrate can convert the lead salt precursor and the second salt precursor into a perovskite material (e.g., FAPbI3, GAPb(SCN)3, FASnI3). Annealing can be performed in a variety of atmospheres, including atmospheric pressure (e.g., about 1 atmosphere, depending on altitude and atmospheric conditions) or subatmospheric pressure (e.g., 1 mTorr to 500 mTorr). The annealing atmosphere can be ambient air, a controlled humidity environment (e.g., 0 to 100 g of HO / m of gas), or a controlled humidity environment (e.g., 0 to 100 g of HO / m of gas). 3The controlled humidity environment may include an environment in which the absolute humidity or % relative humidity is held at a fixed value, or an environment in which the absolute humidity or % relative humidity is varied according to a predetermined set point or function. In some embodiments, annealing may occur in a controlled humidity environment with a relative humidity between 0% and 50%. In other embodiments, annealing may occur in a controlled humidity environment with a relative humidity of 0 g HO / m 3 More than 20g H2O / m 3 Annealing can be performed in a controlled humidity environment containing the following gases: In one embodiment, annealing can be performed at a temperature between 50° C. and 300° C. Unless otherwise specified, any annealing or deposition step described herein can be performed under the above conditions.

[0094]

[0128] For example, in one embodiment, FAPbI3 perovskite material can be formed by the following process. First, a lead halide precursor (II) containing PbI2 to PbCl2 in a molar ratio of approximately 90:10 dissolved in anhydrous DMF can be deposited onto a substrate by spin coating or slot die printing. The lead halide precursor ink can be dried for approximately 1 hour (+15 minutes) in a substantially water-free atmosphere, i.e., an atmosphere with a relative humidity of less than 30%, to form a thin film. The thin film can then be thermally annealed at approximately 50°C (+10°C) for approximately 10 minutes. In other embodiments, the lead halide precursor can be deposited by inkjet printing, gravure printing, screen printing, sputtering, PE-CVD, atomic layer deposition, thermal evaporation, or spray coating. Next, a formamidinium iodide precursor containing formamidinium iodide at a concentration of 25-60 mg / mL dissolved in anhydrous isopropyl alcohol can be deposited onto the lead halide thin film by spin coating or slot die printing. In other embodiments, the formamidinium iodide precursor can be deposited by inkjet printing, gravure printing, screen printing, sputtering, PE-CVD, atomic layer deposition, thermal evaporation, or spray coating. After depositing the lead halide precursor and formamidinium iodide precursor, the substrate is heated to about 25% relative humidity (about 4-7 g HO / m 3 The resulting solution can be annealed in air at temperatures between about 125°C and 200°C to form formamidinium lead iodide (FAPbI3) perovskite material.

[0095]

[0129] In another embodiment, the perovskite material may comprise C'CPbX3, where C' is one or more Group 1 metals (i.e., Li, Na, K, Rb, Cs). In some embodiments, M' may be cesium (Cs). In other embodiments, C' may be rubidium (Rb). In other embodiments, C' may be sodium (Na). In other embodiments, C' may be potassium (K). In yet other embodiments, the perovskite material may comprise C'vCwPbyXz, where C' is one or more Group 1 metals and v, w, y, and z are real numbers between 1 and 20. In some embodiments, the perovskite material may be deposited as an active layer onto a substrate layer using the processes described below, for example, by drop casting, spin casting, gravure coating, blade coating, reverse gravure coating, slot-die printing, screen printing, or inkjet printing.

[0096]

[0130] First, a lead halide solution is generated. A quantity of lead halide can be masked in a clean, dry container under a controlled atmosphere. Suitable lead halides include, but are not limited to, lead(II) iodide, lead(II) bromide, lead(II) chloride, and lead(II) fluoride. The lead halide can consist of a single lead halide species or a mixture of lead halides in precise ratios. In some embodiments, the lead halide mixture can consist of any binary, ternary, or quaternary ratio of 0.001 to 100 mole percent iodide, bromide, chloride, or fluoride. In one embodiment, the lead halide mixture can include lead(II) chloride and lead(II) iodide in a mole:mol ratio of about 10:90. In other embodiments, the lead halide mixture may include lead(II) chloride and lead(II) iodide in a ratio of about 5:95, about 7.5:92.5, or about 15:85 mole:molar.

[0097]

[0131] Alternatively, other lead salt precursors can be used in combination with or in place of the lead halide salt to form the lead salt solution. Suitable precursor salts may include lead(II) or lead(IV) in any combination with the following anions: nitrate, nitrite, carboxylate, acetate, formate, oxalate, sulfate, sulfite, thiosulfate, phosphate, tetrafluoroborate, hexafluorophosphate, tetra(perfluorophenyl)borate, hydride, oxide, peroxide, hydroxide, nitride, arsenate, arsenite, perchlorate, carbonate, bicarbonate, chromate, dichromate, iodate, bromate, chlorate, chlorite, hypochlorite, hypobromite, cyanide, cyanate, isocyanate, fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate, carbamoyldicyanomethanide, dicyanonitrosomethane, dicyanamide and tricyanomethanide, tricyanomethanide, amide, and permanganate.

[0098]

[0132] The lead salt solution may further contain, as a salt of the anion, a lead(II) salt or a lead(IV) salt in a molar ratio of 0 to 100% relative to the following metal ions: Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr.

[0099]

[0133] A solvent can then be added to the container to dissolve the lead halide solids and form the lead halide precursor ink. Suitable solvents include, but are not limited to, dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethyl sulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof. In one embodiment, the lead solids are dissolved in dry dimethylformamide (DMF). The lead solids can be dissolved at a temperature of about 20-150°C. In one embodiment, the lead solids can be dissolved at about 85°C and allowed to dissolve as long as necessary to form a solution, which may be up to about 72 hours. The resulting solution forms the base of the lead halide precursor ink. In some embodiments, the lead halide concentration of the lead halide precursor ink may be from about 0.001 M to about 10 M. In one embodiment, the lead halide concentration of the lead halide precursor ink may be about 1 M. In some embodiments, the lead halide solution may further include an amino acid (e.g., 5-aminovaleric acid, histidine, glycine, lysine), an amino acid hydrogen halide (e.g., 5-aminovaleric acid hydrochloride), an IFL surface modifying (SAM) agent (e.g., those described hereinabove), or a combination thereof.

[0100]

[0134] A Group 1 metal halide solution is then formed. The amount of Group 1 metal halide can be masked in a clean, dry container under a controlled atmosphere. Suitable Group 1 metal halides include, but are not limited to, cesium iodide, cesium bromide, cesium chloride, cesium fluoride, rubidium iodide, rubidium bromide, rubidium chloride, rubidium fluoride, lithium iodide, lithium bromide, lithium chloride, lithium fluoride, sodium iodide, sodium bromide, sodium fluoride, potassium iodide, potassium bromide, potassium chloride, and potassium fluoride. The Group 1 metal halide may comprise a single species of Group 1 metal halide or may comprise a mixture of Group 1 metal halides in the correct ratio. In one embodiment, the Group 1 metal halide may comprise cesium iodide. In another embodiment, the Group 1 metal halide may comprise rubidium iodide. In another embodiment, the Group 1 metal halide may comprise sodium iodide. In another embodiment, the Group 1 metal halide may include potassium iodide.

[0101]

[0135] Alternatively, other Group 1 metal salt precursors can be used in combination with or in place of the Group 1 metal halide salts. Suitable precursor Group 1 metal salts may include any combination of Group 1 metals and the following anions: nitrate, nitrite, carboxylate, acetate, formate, oxalate, sulfate, sulfite, thiosulfate, phosphate, tetrafluoroborate, hexafluorophosphate, tetra(perfluorophenyl)borate, hydride, oxide, peroxide, hydroxide, nitride, arsenate, arsenite, perchlorate, carbonate, bicarbonate, chromate, sulfite, dichromate, iodate, bromate, chlorate, chlorite, hypochlorite, hypobromite, cyanide, cyanate, isocyanate, fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate, carbamoyldicyanomethanide, dicyanonitrosomethane, dicyanamide and tricyanomethanide, tricyanomethanide, amide, and permanganate.

[0102]

[0136] A solvent can then be added to the vessel to dissolve the Group 1 metal halide solids to form a Group 1 metal halide solution. Suitable solvents include, but are not limited to, dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethylsulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof. In one embodiment, the Group 1 metal halide solids are dissolved in dry dimethylformamide (DMF). The Group 1 metal halide solids can be dissolved at a temperature of about 20 to 150°C. In one embodiment, the Group 1 metal halide solids are dissolved at room temperature (i.e., about 25°C). The Group 1 metal halide solids are allowed to dissolve for as long as necessary to form a solution, which may occur for up to about 72 hours. The resulting solution forms a Group 1 metal halide solution. In some embodiments, the Group 1 metal halide solution may have a lead halide concentration of about 0.001 M to about 10 M. In one embodiment, the Group 1 metal halide solution may have a lead halide concentration of about 1 M. In some embodiments, the Group 1 metal halide solution may further comprise an amino acid (e.g., 5-aminovaleric acid, histidine, glycine, lysine), an amino acid hydrogen halide (e.g., 5-aminovaleric acid hydrochloride), an IFL surface modifying (SAM) agent (e.g., those described hereinabove), or a combination thereof.

[0103]

[0137] Next, the lead halide solution and the Group 1 metal halide solution are mixed to form a thin film precursor ink. The lead halide solution and the Group 1 metal halide solution may be mixed so that the molar concentration ratio of the Group 1 metal halide in the resulting thin film precursor ink is between 0% and 25% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 1% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 5% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 10% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 15% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 20% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of Group 1 metal halide that is 25% of the molar concentration of lead halide. In some embodiments, the lead halide solution and the Group 1 metal halide solution may be stirred or agitated during or after mixing.

[0104]

[0138] The thin film precursor ink can then be deposited onto a desired substrate. Suitable substrate layers may include any of the substrate layers identified previously in this disclosure. As noted above, the thin film precursor ink can be deposited via a variety of means, including, but not limited to, drop casting, spin casting, gravure coating, blade coating, reverse gravure coating, slot-die printing, screen printing, or inkjet printing. In some embodiments, the thin film precursor ink can be spin-coated onto a substrate at a speed of about 500 rpm to about 10,000 rpm for a period of about 5 seconds to about 600 seconds. In one embodiment, the thin film precursor ink can be spin-coated onto a substrate at about 3000 rpm for about 30 seconds. The thin film precursor ink can be deposited onto a substrate in an ambient atmosphere with a humidity range of about 0% relative humidity to about 50% relative humidity. The thin film precursor ink can then be deposited in a substantially water-free atmosphere, i.e., a relative humidity of less than 30%, or 7 g HO / m 3 The solution may be dried at less than 100° C. to form a thin film.

[0105]

[0139] The thin film can then be thermally annealed at a temperature of about 20°C to about 300°C for a period of up to about 24 hours. In one embodiment, the thin film can be thermally annealed at a temperature of about 50°C for about 10 minutes. The perovskite material active layer can then be completed by a conversion process in which the precursor film is immersed or rinsed in a salt solution containing a solvent or mixture of solvents (e.g., DMF, isopropanol, methanol, ethanol, butanol, chloroform, chlorobenzene, dimethyl sulfoxide (DMSO), water) at a concentration of 0.001M to 10M and a salt (e.g., methylammonium iodide, formamidinium iodide, guanidinium iodide, 1,2,2-triaminovinylammonium iodide, 5-aminovaleric acid hydrochloride). In some embodiments, the perovskite material thin film can also be thermally post-annealed in the same manner as in the first line of this paragraph.

[0106]

[0140] In some embodiments, the salt solution can be prepared by massing salts in a clean, dry container under a controlled atmosphere. Suitable salts include, but are not limited to, methylammonium iodide, formamidinium iodide, guanidinium iodide, imidazolium iodide, ethenetetramine iodide, 1,2,2-triaminovinylammonium iodide, and 5-aminovaleric acid hydroiodide. Other suitable salts can include any of the organic cations listed under "Perovskite Materials," and the salts can include a single salt or a mixture of salts in precise ratios. In one embodiment, the salt can include methylammonium iodide. In another embodiment, the salt can include formamidinium iodide. A solvent can then be added to the container to dissolve the salt solids and form the salt solution. Suitable solvents include, but are not limited to, DMF, acetonitrile, isopropanol, methanol, ethanol, butanol, chloroform, chlorobenzene, dimethyl sulfoxide (DMSO), water, and combinations thereof. In one embodiment, a formamidinium iodide salt solid is dissolved in isopropanol. The salt solid can be dissolved at about 20 to about 150°C. In one embodiment, the salt solid is dissolved at room temperature (i.e., about 25°C). The salt solid is allowed to dissolve for as long as necessary to form a solution, which can occur over a period of up to about 72 hours. The resulting solution forms a salt solution. In some embodiments, the salt concentration of the salt solution can be about 0.001 M to about 10 M. In one embodiment, the salt concentration of the salt solution is about 1 M.

[0107]

[0141] For example, using the above method with lead(II) iodide solution, cesium iodide solution, and methylammonium iodide (MA) salt solution, the compound of formula Cs i MA 1-i PbI3, where i is a number between 0 and 1. As another example, a perovskite material of the formula Rb can be obtained by using a lead(II) iodide solution, a rubidium iodide solution, and a formamidinium iodide (FA) salt solution. i FA 1-iPbI3, where i is a number between 0 and 1. As another example, a lead(II) iodide solution, a cesium iodide solution, and a formamidinium iodide (FA) salt solution can be used to obtain a perovskite material of the formula Cs i FA 1-i PbI3, where i is a number between 0 and 1. As another example, a lead(II) iodide solution, a potassium iodide solution, and a formamidinium iodide (FA) salt solution can be used to obtain a perovskite material of the formula K i FA 1-i PbI3, where i is a number between 0 and 1. As another example, a perovskite material of the formula NaI can be obtained by using a lead(II) iodide solution, a sodium iodide solution, and a formamidinium iodide (FA) salt solution. i FA 1-i PbI3 (where i is a number between 0 and 1) can be obtained. As another example, a lead(II) iodide-chloride(II) mixed solution, a cesium iodide solution, and a formamidinium iodide (FA) salt solution can be used to obtain a perovskite material of the formula Cs i FA 1-i PbI 3-y Cl y (wherein i is a number between 0 and 1, and y is a number between 0 and 3) can be obtained.

[0108]

[0142] In some embodiments, the lead halide solution may have a molar ratio of PbI2 to PbCl2 of 90:10. A cesium iodide (CsI) solution can be added to the lead halide solution using the method described above to form a thin-film precursor ink containing 10 mol% CsI. FAPbI3 perovskite materials can be produced using this thin-film precursor solution using the method described above. Adding cesium ions using the CsI solution as described above can result in chloride anions and cesium atoms being incorporated into the FAPbI3 crystal lattice. This may result in a greater degree of lattice contraction than adding cesium or rubidium ions without adding chloride ions as described above. Table 1 below shows the lattice parameters for FAPbI3 perovskite materials containing 10 mol% rubidium and 20 mol% chloride (e.g., 10 mol% PbCl2), 10 mol% cesium, and 10 mol% cesium with 20 mol% chloride. Here, the mole percent concentration represents the concentration of the additive relative to the lead atoms in the lead halide solution. As can be seen in Table 1, the lattice parameters of the FAPbI3 perovskite material doped with cesium and chloride are smaller than those of the other two perovskite material samples.

[0109] [Table 1]

[0143] Furthermore, data indicate that the cubic structure of FAPbI3 perovskite materials doped with rubidium, cesium, and / or chloride is a Pm3-m cubic structure. FAPbI3 perovskites containing 10 mol% Rb and 10 mol% Cl, or 10 mol% Cs, or 10 mol% Cs and 10 mol% Cl have been observed to maintain the cubic Pm3-m cubic structure. Figure 29 shows the X-ray diffraction patterns corresponding to each sample listed in Table 1. Tables 2-4 show the X-ray diffraction peaks and intensities for the three perovskite materials listed in Table 1. Data were collected at ambient conditions using a Rigaku Miniflex 600 with a Cu Kα radiation source at a scan rate of 1.5 degrees 2θ / min.

[0110] [Table 2]

[0111] [Table 3]

[0112] [Table 4]

[0144] The geometrically predicted X-ray diffraction patterns under Cu-Kα radiation for a cubic Pm3-m material with a lattice constant of 6.3375 Å are shown in Table 5. As can be seen from the data, the diffraction patterns of the perovskite materials prepared with 10 mol% Rb and 10 mol% Cl, 10 mol% Cs, and 10% Cs and 10% Cl each match the pattern expected for a cubic Pm3-m perovskite material.

[0113] [Table 5]

[0145] Enhanced Perovskite So-called "layered" 2D perovskites are known to form when perovskites are formulated using organic cations with longer alkyl chains than the methylammonium and formamidinium cations described hereinabove. Layered 2D perovskites include structures such as the Ruddlesden-Popper phase, the Dion-Jacobson phase, and the Aurivillius phase. For example, by substituting 1-butylammonium for the methylammonium or other cations described above, the Ruddlesden-Popper 2D perovskite can be produced during perovskite formation by a "one-step" method (not described herein). In such perovskites, the 1-butylammonium prevents the perovskite from forming a perfect crystal lattice; instead, the perovskite forms "sheets" of perovskite with a single crystal structure throughout its thickness. Figure 5 shows the structure of the Ruddlesden-Popper perovskite 5500 with the 1-butylammonium cation 5510. As can be seen in Figure 5, the "tails" of the butylammonium cations 5510 provide separation between the lead and iodide portions of the perovskite material and other lead and iodide structures, resulting in 2D perovskite "sheets." Therefore, it would be undesirable to introduce "bulky" organic cations, such as 1-butylammonium or benzylammonium, during the formation of the perovskite material if the Raddelsen-Popper morphology of the perovskite is undesirable.

[0146] However, adding a dilute amount of 1-butylammonium solution to the perovskite material before annealing it may result in the formation of a perovskite, as shown in FIG. 6. FIG. 6 shows an embodiment of a perovskite material 2000 with the addition of alkylammonium cations for surface passivation. In the illustrated embodiment, the surface of formamidinium lead iodide (FAPbI) perovskite material 2010 is shown with 1-butylammonium cations 2020 on the surface. In some examples, the 1-butylammonium cations, or other "bulky" organic cations as described herein, can diffuse into the perovskite material near the surface of the crystal lattice of the perovskite material. In some embodiments, the 1-butylammonium cations, or other "bulky" organic cations as described herein, can reside no more than 50 nm into the perovskite material from the crystal lattice surface or grain boundary. The inclusion of "bulky" organic cations, such as 1-butylammonium, near or on the surface of the perovskite material can cause the formula of the perovskite material to deviate from the "ideal" stoichiometry of the perovskite materials disclosed herein. For example, the inclusion of such organic cations can cause the perovskite material to have a formula that is either sub-stoichiometric or super-stoichiometric with respect to the formula CMX3 described herein. In this case, the general formula of the perovskite material can be represented as CxMyXz, where x, y, and z are real numbers. In some embodiments, the perovskite material has the formula C'C n-1 M n X 3n+1 where n is an integer. For example, when n=1, the perovskite material can be represented by the formula C'MX, when n=2, the perovskite material can be represented by the formula C'CMX, and when n=3, the perovskite material can be represented by the formula C'CMCX. 10 and when n=4, the perovskite material has the formula C'2C3M4X 13 As shown in Figure 30, the n value indicates the thickness of the inorganic metal halide sublattice of the perovskite material. n-1 M nX 3n+1 Phases of perovskite materials represented by the formula (I) can form in regions where bulky organic cations have diffused or otherwise penetrated into the crystal lattice of the perovskite material. For example, such phases can exist within 50 nanometers of a crystal lattice surface (e.g., a surface or grain boundary) of a perovskite material comprising bulky organic cations as disclosed herein.

[0114]

[0147] The carbon "tail" of the 1-butylammonium ion can provide protective properties to the surface of the perovskite by effectively repelling other molecules from the surface. In some embodiments, the alkyl group "tail" of the 1-butylammonium ion can be oriented away from or parallel to the surface of the perovskite material. In particular, the 1-butylammonium "tail" has hydrophobic properties that prevent water molecules from contacting the surface of the perovskite, protecting the surface of the perovskite material 2010 from environmental water. In addition, the 1-butylammonium cation can also act to passivate the surface and any grain boundaries or defects in the perovskite material 2010. Passivation refers to the electrical property of preventing charge accumulation or "trap states" at the surface or grain boundaries of the perovskite material 2010. By acting to passivate portions of the perovskite material 2010, the 1-butylammonium can improve charge transport in and out of the perovskite material 2010, improving the electrical properties of the photoactive layer.

[0115]

[0148] In some embodiments, other organic cations can be used in place of or in combination with 1-butylammonium. Examples of other "bulky" organic cations that may be effective in passivating the surface of perovskite materials include, but are not limited to, ethylammonium, propylammonium, n-butylammonium; perylene n-butylamine imide; butane-1,4-diammonium; 1-pentylammonium; 1-hexylammonium; poly(vinylammonium); phenylethylammonium; benzylammonium; 3-phenyl-1-propylammonium; 4-phenyl-1-butylammonium; 1,3-dimethylbutylammonium; 3,3-dimethylbutylammonium; 1-heptylammonium; 1-octylammonium; 1-nonylammonium; 1-decylammonium; and 1-icosanylammonium (eicosanylammonium). Furthermore, in bulky organic cations with tails containing one or more heteroatoms in addition to the cationic species, the heteroatoms can coordinate, bond, or become integral with the perovskite material crystal lattice. A heteroatom can be any atom of the tail that is not hydrogen or carbon, including nitrogen, sulfur, oxygen, or phosphorus.

[0116]

[0149] Other examples of "bulky" organic cations include ammonium groups, phosphonium groups, or other cationic groups that can be incorporated into the "C-site of the perovskite material": benzene, pyridine, naphthalene, anthracene, xanthene, phenanthrene, tetracene, chrysene, tetraphene, benzo[c]phenanthrene, triphenylene, pyrene, perylene, corannulene, coronene, substituted dicarboxylic acid imides, aniline, N-(2-aminoethyl)-2-isoindole-1,3-dione, 2-(1-aminoethyl)naphthalene, 2-isoindole-1,3-dione ... -triphenylene-O-ethylamine ether, benzylamine, benzylammonium salt, Nn-butyl-N'-4-aminobutylperylene-3,4,9,10-bis(dicarboximide), 1-(4-alkylphenyl)methanamine, 1-(4-alkyl-2-phenyl)ethanamine, 1-(4-alkyl-2-phenyl)methanamine, 1-(3-alkyl-5-alkylphenyl)methanamine, 1-(3-alkyl-5-alkyl-2-phenyl)ethanamine, 1-(4-alkyl -2-phenyl)ethanamine, 2-ethylamine-7-alkyl-naphthalene, 2-ethylamine-6-alkyl-naphthalene, 1-ethylamine-7-alkyl-naphthalene, 1-ethylamine-6-alkyl-naphthalene, 2-methylamine-7-alkyl-naphthalene, 2-methylamine-6-alkyl-naphthalene, 1-methylamine-7-alkyl-naphthalene, 1-methylamine-6-alkyl-naphthalene, Nn-aminoalkyl-N'-4-aminobutylperylene-3,4,9,10-bis(dicarboximide) , 1-(3-butyl-5-methoxybutylphenyl)methanamine, 1-(4-pentylphenyl)methanamine, 1-[4-(2-methylpentyl)-2-phenyl]ethanamine, 1-(3-butyl-5-pentyl-2-phenyl)ethanamine, 2-(5-[4-methylpentyl]-2-naphthyl)ethanamine, N-7-tridecyl-N'-4-aminobutylperylene-3,4,9,10-bis(dicarboximide), Nn-heptyl-N'-4-aminobutylperylene-3,4,9,10-bis(dicarboximide),Included are the following molecules functionalized with 2-(6-[3-methoxylpropyl]-2-naphthyl)ethanamine. Figures 17-28 illustrate the structures of these organic molecules, according to certain embodiments. With reference to Figures 17 and 18, each "R group," Rx, can be H, R', Me, Et, Pr, Ph, Bz, F, Cl, Br, I, NO2, OR', NR'2, SCN, CN, N3, or SR', where R' can be any alkyl, alkenyl, or alkynyl chain. Additionally, at least one of the depicted R groups can be (CH)EX or (CH)C(EX), where n and y can be equal or unequal, E can be selected from the group consisting of C, Si, O, S, Se, Te, N, P, As, or B, and X is a halide or pseudohalide, such as F, Cl, Br, I, CN, SCN, or H. Additionally, with respect to Figure 19, the depicted molecule can include any hydrohalide, e.g., benzylammonium salt, of each depicted amine, where the depicted X group can be F, Cl, Br, I, SCN, CN, or any other pseudohalide. Other non-halide tolerant anions include, but are not limited to, nitrate, nitrite, carboxylate, acetate, acetonylacetonate, formate, oxalate, sulfate, sulfite, thiosulfate, phosphate, tetrafluoroborate, hexafluorophosphate, tetra(perfluorophenyl)borate, hydride, oxide, peroxide, hydroxide, nitride, arsenate, arsenite, perchlorate, carbonate, bicarbonate, chromate, sulfite, dichromate, iodate, bromate, chlorate, chlorite, hypochlorite, hypobromite, cyanide, cyanate, isocyanate, fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate, carbamoyldicyanomethanide, dicyanonitrose, dicyanamide and tricyanomethanide, tricyanomethanide, amide, and permanganate. Suitable R groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl groups or isomers thereof; alkanes, alkenes or alkynes CxHy (x=1-20, y=1-42, cyclic, branched or linear); alkyl halides, alkyl halides CxHyXz, where:x=1 to 20, y=0 to 42, z=1 to 42, X=F, Cl, Br, or I); any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes containing at least one nitrogen in the ring (e.g., pyridine, pyrrole, pyrrolidine, piperidine, tetrahydroquinoline); any sulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group (nitroxide, amine); any phosphorus-containing group (phosphate); any Examples of suitable organic compounds include, but are not limited to, boron-containing groups (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid) and its ester or amide derivatives; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histidine, 5-ammonium valerate), including α, β, γ and higher derivatives; any silicon-containing group (e.g., siloxane); and any alkoxy or group, —OCxHy (where x=0-20, y=1-42).

[0117]

[0150] Additionally, in some embodiments, bulky organic cations may passivate grain boundaries and surface defects in the perovskite material. Figure 7 shows an example of a perovskite material layer 3000 in which 1-butylammonium cations 3020 passivate both the surface and grain boundaries 3015 of the bulk perovskite material 3010. As noted above, the alkyl tails of these ions can also form a hydrophobic layer that repels water and other polar species, preventing them from reaching the surface of the perovskite material. As seen in Figure 7, the "tail" of the bulky organic cation may not be chemically bonded (e.g., covalently or ionically) to the surface or grain boundaries 3015 of the perovskite material layer 3000. As used herein, the "tail" of any bulky organic cation refers to the non-ionic carbon structure of the bulky organic cation. For example, the tail of 1-butylammonium is a butyl group, and the tail of benzylammonium is a benzyl group.

[0118]

[0151] The tails of the bulky organic cations can also adopt other configurations with respect to the surface or grain boundaries of the perovskite material. Generally, the cationic "heads" of the bulky organic cations do not diffuse more than 50 nanometers beyond the surface or grain boundaries of the perovskite material. The tails interact weakly with the perovskite material and are oriented away from the perovskite material grain surfaces. The tails may have intermolecular interactions (e.g., dipole-dipole or hydrogen bonding) with the perovskite material grain surfaces, resulting in an orientation of the tails oriented toward the perovskite material grain surfaces. In some embodiments, the tails of some bulky organic cations present in the perovskite material may not interact with the surface or grain boundaries of the perovskite material, while the tails of other bulky organic cations in the perovskite material may interact with the surface or grain boundaries of the perovskite material. The tails may comprise heteroatoms or anions (i.e., zwitterions) with at least one lone pair of electrons that can covalently interact with the perovskite material grain surface through metal atoms (e.g., Pb, Sn, Ge, In, Bi, Cu, Ag, Au) present in the perovskite material. The tails may also comprise cationic species, such as diammonium butane, as described herein, which can be incorporated into the perovskite material by substituting on at least two "C" cation sites (e.g., formamidinium). Tail segments containing cationic species can also bridge two layers of the 2D perovskite material, tilt across the perovskite material grain surface, or orient away from the perovskite material grain surface, similar to the manner described for nonionic tail segments. In other embodiments, bulky organic cations with sufficiently large tails, such as imidazolium cations, may simply reside on the perovskite surface or grain boundaries without diffusing into the perovskite material.

[0119]

[0152] Additionally, in other embodiments, bulky organic cations with different tail group lengths or sizes can be applied to the perovskite to passivate grain boundaries and surface defects in the perovskite material. Figure 8 shows an example of a perovskite material layer 4000 with a combination of 1-butylammonium 4020, 1-nonylammonium 4021, 1-heptylammonium 4022, and 1-hexylammonium 4023, which passivates both the surface and grain boundaries 4015 of the bulk perovskite material 4010. In some embodiments, mixtures of any of the alkylammonium compounds identified above can be applied to the perovskite material as described herein. Figure 8 shows an example of a perovskite material layer 4000 with a combination of 1-butylammonium 4020, 1-nonylammonium 4021, 1-heptylammonium 4022, and 1-hexylammonium 4023, which passivates both the surface and grain boundaries 4015 of the bulk perovskite material 4010. In some embodiments, mixtures of any of the alkylammonium compounds identified above may be applied to the perovskite material as described herein. In some embodiments, the bulky organic cation may comprise a benzyl group. Figure 8A shows an example of a perovskite material layer 45500 with various bulky organic cations, including benzyl groups, which passivate both the surface and grain boundaries 4515 of the bulk perovskite material 4510.

[0120]

[0153] As discussed above, adding a 1-butylammonium surface coating to perovskite materials has been shown to enhance the high-temperature durability of perovskite in humid environments. Figure 9 shows a comparison of images of perovskite materials with and without a 1-butylammonium ("BAI") surface coating over a 48-day period. Both perovskite materials have the same composition and were exposed to an environment with a temperature of 85°C and 55% relative humidity for 48 days. As can be seen from the photographs, the perovskite material without the 1-butylammonium surface coating significantly faded in color after one day of exposure to the environment, indicating significant degradation of the perovskite material. The perovskite material with the 1-butylammonium surface coating gradually lightened over the 48 days and remained partially dark after 48 days. This indicates that the perovskite material with the 1-butylammonium surface coating is more robust during long-term exposure to high-temperature environments than the perovskite material without the 1-butylammonium surface coating.

[0121]

[0154] Figure 10 shows a comparison of images of perovskite materials with and without a 1-butylammonium ("BAI") surface coating over a seven-day period. Both perovskite materials have the same composition and were exposed to an 85°C environment with 0% relative humidity for 48 days. As can be seen from the photographs, the perovskite material without the 1-butylammonium surface coating significantly faded in color after one day of exposure to the environment, indicating significant degradation of the perovskite material. The perovskite material with the 1-butylammonium surface coating shows almost no color change after seven days. This indicates that the perovskite material with the 1-butylammonium surface coating was not completely destroyed during long-term exposure to a high-temperature, high-humidity environment.

[0122]

[0155] In other embodiments, perylene n-butylamine imide can be applied to the surface of a perovskite material as described above for 1-butylammonium. Figures 11A-D show various perylene monoimides and diimides that can be applied to the surface of a perovskite material according to the present disclosure. Figure 12 shows an embodiment of a perovskite material 2500 with the addition of an alkylammonium cation for surface passivation. In the illustrated embodiment, the surface of a formamidinium lead iodide (FAPbI) perovskite material 2510 is shown with perylene n-butylamine imide 2520 on the surface. Similar to 1-butylammonium shown in Figure 6, the carbon "tail" of the perylene n-butylamine imide ion can provide protective properties to the surface of the perovskite by effectively repelling other molecules from the surface. In particular, the perylene n-butylamine imide "tail" is hydrophobic, preventing water molecules from contacting the surface of the perovskite, protecting the surface of the perovskite material 2510 from environmental water. In addition, the perylene n-butylamine imide cation may also act to passivate the surface and any grain boundaries or defects in the perovskite material 2510. By acting to passivate a portion of the perovskite material 2510, the perylene n-butylamine imide may promote improved charge transport in and out of the perovskite material 2510, improving the electrical properties of the photoactive layer.

[0123]

[0156] An exemplary method for depositing 1-butylammonium prior to annealing the perovskite material is described below.

[0124]

[0157] First, a lead halide precursor ink is formed. A quantity of lead halide can be masked in a clean, dry container in a controlled atmosphere environment (e.g., a controlled atmosphere box with a porthole containing gloves allows for manipulation of the material in an airless environment). Suitable lead halides include, but are not limited to, lead(II) iodide, lead(II) bromide, lead(II) chloride, and lead(II) fluoride. The lead halide may consist of a single lead halide species or a mixture of lead halides in precise ratios. In some embodiments, the lead halide mixture may consist of any binary, ternary, or quaternary ratio of 0.001 to 100 mole percent iodide, bromide, chloride, or fluoride. In one embodiment, the lead halide mixture may include lead(II) chloride and lead(II) iodide in a mole:mol ratio of about 10:90. In other embodiments, the lead halide mixture may include lead(II) chloride and lead(II) iodide in a ratio of about 5:95, about 7.5:92.5, or about 15:85 mole:molar.

[0125]

[0158] Alternatively, other lead salt precursors can be used in conjunction with or in place of the lead halide salts to form the precursor ink. Suitable precursor salts may include lead(II) or lead(IV) in combination with any of the following anions: nitrate, nitrite, carboxylate, acetate, acetonylacetonate, formate, oxalate, sulfate, sulfite, thiosulfate, phosphate, tetrafluoroborate, hexafluorophosphate, tetra(perfluorophenyl)borate, hydride, oxide, peroxide, hydroxide, arsenate, arsenite, perchlorate, carbonate, bicarbonate, chromate, dichromate, iodate, bromate, chlorate, chlorite, hypochlorite, hypobromite, cyanide, cyanate, isocyanate, fulminate, thiocyanate, isothiocyanate, azide, tetracarbonylcobaltate, carbamoyldicyanomethanide, dicyanonitrosethanide, dicyanamide and tricyanomethanide, tricyanomethanide, amide, and permanganate.

[0126]

[0159] The precursor ink may further contain, as a salt of the anion, a lead(II) salt or a lead(IV) salt in a molar ratio of 0 to 100% relative to the following metal ions: Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr.

[0127]

[0160] A solvent can then be added to the container to dissolve the lead solids and form the lead halide precursor ink. Suitable solvents include, but are not limited to, dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethyl sulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof. In one embodiment, the lead solids are dissolved in dry dimethylformamide (DMF). The lead solids can be dissolved at a temperature of about 20-150°C. In one embodiment, the lead solids can be dissolved at about 85°C and allowed to dissolve as long as necessary to form a solution, which may be for up to about 72 hours. The resulting solution forms the base of the lead halide precursor ink. In some embodiments, the lead halide concentration of the lead halide precursor ink may be from about 0.001 M to about 10 M. In one embodiment, the lead halide concentration of the lead halide precursor ink may be about 1 M. In some embodiments, the lead halide solution may further include an amino acid (e.g., 5-aminovaleric acid, histidine, glycine, lysine), an amino acid hydrogen halide (e.g., 5-aminovaleric acid hydrochloride), an IFL surface modifying (SAM) agent (e.g., those described hereinabove), or a combination thereof.

[0128]

[0161] In some cases, certain additives may be added to the lead halide precursor ink to affect the final perovskite crystallinity and stability. In some embodiments, the lead halide precursor ink may further include an amino acid (e.g., 5-aminovaleric acid, histidine, glycine, lysine), an amino acid hydrogen halide (e.g., 5-aminovaleric acid hydrochloride), an IFL surface modification (SAM) agent (e.g., those described hereinabove), or a combination thereof. In one embodiment, formamidinium chloride may be added to the lead halide precursor ink. In other embodiments, halides of any of the cations described hereinabove may be used. In some embodiments, a combination of additives may be added to the lead halide precursor ink, including, for example, a combination of formamidinium chloride and 5-aminovaleric acid chloride.

[0129]

[0162] The additives, including formamidinium chloride and / or 5-aminovalerate chloride, can be added to the lead halide precursor ink at various concentrations depending on the desired properties of the resulting perovskite material. In one embodiment, the additives can be added at a concentration of about 1 nM to about 1 M. In another embodiment, the additives can be added at a concentration of about 1 μM to about 1 M. In another embodiment, the additives can be added at a concentration of about 1 μM to about 1 mM.

[0130]

[0163] In some embodiments, a Group 1 metal halide solution is formed for addition to the lead halide precursor ink. The amount of Group 1 metal halide can be masked in a clean, dry container under a controlled atmosphere. Suitable Group 1 metal halides include, but are not limited to, cesium iodide, cesium bromide, cesium chloride, cesium fluoride, rubidium iodide, rubidium bromide, rubidium chloride, rubidium fluoride, lithium iodide, lithium bromide, lithium chloride, lithium fluoride, sodium iodide, sodium bromide, sodium fluoride, potassium iodide, potassium bromide, potassium chloride, and potassium fluoride. The Group 1 metal halide may comprise a single species of Group 1 metal halide or a mixture of Group 1 metal halides in the correct ratio. In one embodiment, the Group 1 metal halide may comprise cesium iodide. In another embodiment, the Group 1 metal halide may comprise rubidium iodide. In another embodiment, the Group 1 metal halide may include sodium iodide.In another embodiment, the Group 1 metal halide may include potassium iodide.

[0131]

[0164] Alternatively, other Group 1 metal salt precursors can be used in conjunction with or in place of the Group 1 metal halide salt to form the Group 1 metal salt solution. Suitable precursor Group 1 metal salts may include any combination of nitrates, nitrites, carboxylates, acetates, formates, oxalates, sulfates, sulfites, thiosulfates, phosphates, tetrafluoroborate, hexafluorophosphate, tetra(perfluorophenyl)borate, hydrides, oxides, peroxides, hydroxides, nitrides, arsenates, arsenites, perchlorates, carbonates, bicarbonates, chromates, iodates, bromates, chlorates, chlorites, hypochlorites, hypobromites, cyanates, cyanates, isocyanates, thiocyanates, isothiocyanates, azides, tetracarbonylcobaltates, carbamoyldicyanomethanes, dicyanonitroses, dicyanamides and tricyanomethanes, amides, and permanganates.

[0132]

[0165] A solvent can then be added to the vessel to dissolve the Group 1 metal halide solids to form a Group 1 metal halide solution. Suitable solvents include, but are not limited to, dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethylsulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof. In one embodiment, the Group 1 metal halide solids are dissolved in dry dimethylformamide (DMF). The Group 1 metal halide solids can be dissolved at a temperature of about 20 to 150°C. In one embodiment, the Group 1 metal halide solids are dissolved at room temperature (i.e., about 25°C). The Group 1 metal halide solids are allowed to dissolve for as long as necessary to form a solution, which may occur for up to about 72 hours. The resulting solution forms a Group 1 metal halide solution. In some embodiments, the Group 1 metal halide solution may have a lead halide concentration of about 0.001 M to about 10 M. In one embodiment, the Group 1 metal halide solution may have a lead halide concentration of about 1 M. In some embodiments, the Group 1 metal halide solution may further comprise an amino acid (e.g., 5-aminovaleric acid, histidine, glycine, lysine), an amino acid hydrogen halide (e.g., 5-aminovaleric acid hydrochloride), an IFL surface modifying (SAM) agent (e.g., those described hereinabove), or a combination thereof.

[0133]

[0166] Next, the lead halide solution and the Group 1 metal halide solution are mixed to form a thin film precursor ink. The lead halide solution and the Group 1 metal halide solution may be mixed so that the molar concentration of the Group 1 metal halide in the resulting thin film precursor ink is between 0% and 25% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 1% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 5% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 10% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 15% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of the Group 1 metal halide of 20% of the molar concentration of the lead halide. In some embodiments, the thin film precursor ink may have a molar concentration of Group 1 metal halide that is 25% of the molar concentration of lead halide. In some embodiments, the lead halide solution and the Group 1 metal halide solution may be stirred or agitated during or after mixing.

[0134]

[0167] Optionally, in some embodiments, water may be added to the lead halide precursor ink. In some embodiments, the solvent may further include 2-methoxyethanol and acetonitrile. In some embodiments, the 2-methoxyethanol and acetonitrile may be added in a volume ratio of about 25:75 to about 75:25, or at least 25:75. In some embodiments, the solvent may include a ratio of 2-methoxyethanol and acetonitrile to DMF of about 1:100 to about 1:1, or about 1:100 to about 1:5, by volume. In some embodiments, the solvent may include a ratio of 2-methoxyethanol and acetonitrile to DMF of at least about 1:100, by volume. For illustrative purposes, and without limiting the disclosure to a particular theory or mechanism, the presence of water affects perovskite thin film crystal growth. Under normal circumstances, water is absorbed as vapor from the air. However, the crystallinity of perovskite PVs can be controlled by directly adding water to the lead halide precursor ink at a specific concentration. Suitable water includes distilled water, deionized water, or other water sources that are substantially free of contaminants (including minerals). Based on optical IV sweeps, the perovskite PV light-to-electrical power conversion efficiency has been found to nearly triple with the addition of water compared to a completely dry device.

[0135]

[0168] Water can be added to the lead halide precursor ink at various concentrations depending on the desired properties of the resulting perovskite material. In one embodiment, water may be added at a concentration of about 1 nL / mL to about 1 mL / mL. In another embodiment, water may be added at a concentration of about 1 μL / mL to about 0.1 mL / mL. In another embodiment, water may be added at a concentration of about 1 μL / mL to about 20 μL / mL.

[0136]

[0169] The lead halide precursor ink or thin film precursor ink can then be deposited on a desired substrate. Suitable substrate layers can include any of the substrate layers described above in this disclosure. As noted above, the lead halide precursor ink or thin film precursor ink can be deposited via a variety of means, including, but not limited to, drop casting, spin casting, slot die printing, screen printing, or inkjet printing. In some embodiments, the lead halide precursor ink or thin film precursor ink can be spin-coated onto a substrate at a speed of about 500 rpm to about 10,000 rpm for a period of about 5 seconds to about 600 seconds. In one embodiment, the lead halide precursor ink or thin film precursor ink can be spin-coated onto a substrate at about 3000 rpm for about 30 seconds. The lead halide precursor ink or thin film precursor ink can be deposited onto a substrate in an ambient atmosphere with a humidity range of about 0% relative humidity to about 50% relative humidity. The lead halide precursor ink or thin film precursor ink can then be dried in a substantially water-free atmosphere, i.e., an atmosphere with a relative humidity of less than 30%, to form a thin film.

[0137]

[0170] After deposition of the lead halide precursor or thin film precursor, the bulky organic cations described above (e.g., benzylammonium, phenylethylammonium, ethylammonium, propylammonium, n-butylammonium; butane-1,4-diammonium; 1-pentylammonium; 1-hexylammonium; poly(vinylammonium); phenylethylammonium; 3-phenyl-1-propylammonium; 4-phenyl-1-butylammonium; 1,3-dimethylbutylammonium; 3,3-dimethylbutylammonium; 1- A salt solution of heptylammonium; 1-octylammonium; 1-nonylammonium; 1-decylammonium; 1-icosanylammonium; or any other bulky cation described herein or illustrated in Figures 17-28 may be applied to the thin film resulting from deposition of the lead salt precursor and the second salt precursor. Bulky organic salts include halides, nitrates, nitrites, carboxylates, acetates, formates, oxalates, sulfates, sulfites, thiosulfates, phosphates, tetrafluoroborate, hexafluorophosphate, tetra(perf), tetra(f)-, ... Examples of bulky organic cation salt solutions include: (fluorophenyl)borates, hydrides, oxides, peroxides, hydroxides, nitrides, arsenates, arsenites, perchlorates, carbonates, bicarbonates, chromates, iodates, bromates, chlorates, chlorites, hypochlorites, hypobromites, cyanates, cyanates, isocyanates, thiocyanates, isothiocyanates, azides, tetracarbonylcobaltates, carbamoyldicyanomethanides, dicyanamides and tricyanomethanides, amides, and permanganates. They can be formed by dissolving bulky organic cation salts in solvents such as alcohol, dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethylsulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridines, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof.In some embodiments, the bulky organic cation salt can be dissolved in isopropyl alcohol. In some embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be 0.0001 M to 1.0 M. In other embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be 0.01 M to 0.1 M. In some embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be 0.02 M to 0.05 M. In some embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be about 0.05 M. The bulky organic cation salt solution can be deposited on the perovskite material precursor thin film by any of the methods described herein for solution deposition. These methods can be deposited by a variety of means, including, but not limited to, spray coating, drop casting, spin casting, blade coating, slot-die printing, screen printing, gravure printing, or inkjet printing. In one embodiment, the bulky organic cation salt can be 1-butylammonium iodide. In another embodiment, the bulky organic cation salt can be benzylammonium iodide. In yet another embodiment, the bulky organic cation salt can be phenylethylammonium iodide.

[0138]

[0171] The thin film can then be thermally annealed at a temperature of about 20°C to about 300°C for a period of up to about 24 hours. In one embodiment, the thin film can be thermally annealed at a temperature of about 50°C for about 10 minutes. The perovskite material active layer can then be completed by a conversion process in which the precursor film is immersed or rinsed in a salt solution containing a solvent or mixture of solvents (e.g., DMF, isopropanol, methanol, ethanol, butanol, chloroform, chlorobenzene, dimethyl sulfoxide (DMSO), water) at a concentration of 0.001M to 10M and a salt (e.g., methylammonium iodide, formamidinium iodide, guanidinium iodide, 1,2,2-triaminovinylammonium iodide, 5-aminovaleric acid hydrochloride). In some embodiments, the perovskite material thin film can also be thermally post-annealed in the same manner as in the first line of this paragraph.

[0139]

[0172] In some embodiments, after annealing, a second salt precursor (e.g., formamidinium iodide, formamidinium thiocyanate, or guanidinium thiocyanate) can be deposited on the lead salt thin film to form a thin film. The temperature of the second salt precursor can be approximately equal to ambient temperature or can be controlled between 0°C and 500°C. The second salt precursor can be deposited by various methods known in the art, including, but not limited to, spin coating, blade coating, slot-die printing, inkjet printing, gravure printing, screen printing, sputtering, PE-CVD, thermal evaporation, and spray coating. In some embodiments, the second salt solution can be subsequently deposited multiple times to form a thin film layer. In some embodiments, the second salt precursor can be a solution containing one or more solvents. For example, the second salt precursor may include one or more of dry N-cyclohexyl-2-pyrrolidone, alkyl-2-pyrrolidone, dimethylformamide (DMF), dialkylformamide, dimethylsulfoxide (DMSO), acetonitrile, methanol, ethanol, propanol, butanol, tetrahydrofuran, formamide, tert-butylpyridine, pyridine, alkylpyridine, pyrrolidine, chlorobenzene, dichlorobenzene, dichloromethane, chloroform, and combinations thereof.

[0140]

[0173] In some embodiments, any bulky organic cation salt described herein can be combined with the second salt solution prior to deposition of the second salt solution. In some embodiments, the bulky organic cation salt solution can be prepared as described above and mixed with the second salt solution prior to deposition of the second salt solution. In some embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be 0.0001 M to 1.0 M. In other embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be 0.01 M to 0.1 M. In some embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be 0.02 M to 0.05 M. In some embodiments, the concentration of the bulky organic cation salt in the bulky organic cation salt solution can be about 0.05 M. The bulky organic cation salt solution can be deposited on a lead halide thin film formed after deposition of a lead halide precursor ink or thin film precursor ink. In other embodiments, a bulky organic cation salt solution may be deposited onto the perovskite precursor thin film after deposition of the second salt solution.

[0141]

[0174] Finally, the substrate with the perovskite material precursor thin film can be annealed. Annealing the substrate converts the lead salt precursor and second salt precursor to a perovskite material (e.g., FAPbI3, GAPb(SCN)3, FASnI3) with a surface passivation layer of bulky organic cations. Annealing can be performed in a variety of atmospheres, including atmospheric pressure (e.g., about 1 atmosphere, depending on altitude and atmospheric conditions) or subatmospheric pressure (e.g., 1 mTorr to 500 mTorr). The annealing atmosphere can be ambient air, a controlled humidity environment (e.g., 0-100 g HO / m of gas), or a controlled humidity environment (e.g., 0-100 g HO / m of gas). 3The controlled humidity environment may include an environment in which the absolute humidity or % relative humidity is held at a fixed value, or an environment in which the absolute humidity or % relative humidity is varied according to a predetermined set point or function. In some embodiments, annealing may occur in a controlled humidity environment with a relative humidity between 0% and 50%. In other embodiments, annealing may occur in a controlled humidity environment with a relative humidity of 0 g HO / m 3 More than 20g H2O / m 3 Annealing can be performed in a controlled humidity environment containing the following gases: In one embodiment, annealing can be performed at a temperature between 50° C. and 300° C. Unless otherwise specified, any annealing or deposition step described herein can be performed under the above conditions.

[0142]

[0175] For example, in one embodiment, FAPbI3 perovskite material can be formed by the following process: First, a lead(II) halide precursor, with a molar ratio of PbI2 to PbCl2 of about 90:10 dissolved in anhydrous DMF, can be deposited onto a substrate by spin coating or slot die printing. The lead halide precursor ink is then applied to a substrate in a substantially water-free atmosphere, i.e., a relative humidity of less than 30% or 17 g HO / m 3 The thin film can be dried at less than 100°C for about 1 hour (+15 minutes) to form a thin film. The thin film can then be thermally annealed at about 50°C (+10°C) for about 10 minutes. In other embodiments, the lead halide precursor can be deposited by inkjet printing, gravure printing, screen printing, blade coating, sputtering, PE-CVD, atomic layer deposition, thermal evaporation, or spray coating. A 0.05M solution of 1-butylammonium salt in isopropyl alcohol can then be deposited on the lead halide thin film. The substrate can be heated to about 25% relative humidity (about 4-7 g H2O / m 3The thin film can be annealed in air (air) and at a temperature between about 100°C and 200°C to form a formamidinium lead iodide (FAPbI3) perovskite material with a surface layer of 1-butylammonium salt. In another embodiment, the 1-butylammonium salt solution can be deposited on the thin film formed after deposition of the formamidinium iodide precursor. In another embodiment, the 1-butylammonium salt solution can be combined with the lead halide precursor ink before deposition of the lead halide precursor ink. In yet another embodiment, the 1-butylammonium salt solution can be combined with the formamidinium iodide precursor before deposition of the formamidinium iodide precursor. In yet another embodiment, the 1-butylammonium salt solution can be deposited on the thin film after deposition of the formamidinium iodide precursor and before annealing the thin film and substrate. In yet another embodiment, the 1-butylammonium salt solution can be deposited on the thin film after annealing the thin film and substrate.

[0143]

[0176] In another embodiment, the above method can be used with lead (II) iodide solution, cesium iodide solution, methylammonium (MA) iodide salt solution, and 1-butylammonium iodide salt solution to produce a compound of formula Cs i MA 1-i PbI3 (where i is a number between 0 and 1) with a 1-butylammonium surface layer may be obtained. As another example, a perovskite material of the formula Rb can be prepared by using a lead(II) iodide solution, a rubidium iodide solution, a formamidinium iodide (FA) salt solution, and a 1-butylammonium salt solution. i FA 1-i It is possible to obtain a perovskite material with a surface layer of PbI3 (where i is a number between 0 and 1) and 1-butylammonium. As another example, lead(II) iodide solution, cesium iodide solution, formamidinium iodide (FA) salt solution, and 1-butylammonium salt solution can be used to obtain a perovskite material with the formula Cs i FA 1-iIt is possible to obtain a perovskite material in which the surface layer of PbI3 (where i is a number between 0 and 1) is 1-butylammonium. As another example, using a lead(II) iodide solution, a potassium iodide solution, a formamidinium iodide (FA) salt solution, and a 1-butylammonium salt solution, the perovskite material of the formula K i FA 1-i It is possible to obtain a perovskite material in which the surface layer of PbI3 (where i is a number between 0 and 1) is 1-butylammonium. As another example, a perovskite material of the formula Na i FA 1-i It is possible to obtain a perovskite material with a surface layer of PbI3 (where i is a number between 0 and 1) and 1-butylammonium. As another example, a lead(II) iodide-lead(II) chloride mixed solution, a cesium iodide solution, a formamidinium iodide (FA) salt solution, and a 1-butylammonium salt solution can be used to obtain a perovskite material with the formula Cs i FA 1-i PbI 3-y Cl y (wherein i is a number between 0 and 1, and y is a number between 0 and 3), a perovskite material in which the surface layer is 1-butylammonium is obtained.

[0144]

[0177] In another embodiment, FAPbI3 perovskite materials can be formed by the following process: First, a lead halide precursor (II) with a molar ratio of PbI2 to PbCl2 of about 90:10 dissolved in anhydrous DMF can be deposited onto a substrate by spin coating or slot die printing. The lead halide precursor ink is deposited in a substantially water-free atmosphere, i.e., a relative humidity of less than 30% or 17 g HO / m 3The thin film can be dried for about 1 hour (+15 minutes) at a temperature of about 50°C (+10°C) for about 10 minutes. In other embodiments, the lead halide precursor can be deposited by inkjet printing, gravure printing, screen printing, sputtering, PE-CVD, atomic layer deposition, thermal evaporation, or spray coating. A formamidinium iodide precursor, comprising formamidinium iodide at a concentration of 15-60 mg / mL dissolved in anhydrous isopropyl alcohol, can then be deposited onto the lead halide thin film by spin coating or blade coating. In other embodiments, the formamidinium iodide precursor can be deposited by inkjet printing, gravure printing, screen printing, slot-die printing, sputtering, PE-CVD, atomic layer deposition, blade coating, thermal evaporation, or spray coating. After depositing the lead halide precursor and formamidinium iodide precursor, a 0.04 M benzylammonium salt solution in isopropyl alcohol may be deposited onto the perovskite material precursor thin film. The substrate is then heated to a relative humidity of about 25% (about 4-7 g HO / m 3 The resulting perovskite material can be annealed at a temperature between about 125°C and 200°C (air) to form a formamidinium lead iodide (FAPbI3) perovskite material. In some embodiments, a benzylammonium salt solution can be deposited on the lead halide thin film prior to deposition of the formamidinium iodide precursor. In other embodiments, a benzylammonium salt solution can be combined with the lead halide precursor ink prior to deposition of the lead halide precursor ink. In yet other embodiments, a benzylammonium salt solution can be combined with the formamidinium iodide precursor prior to deposition of the lead halide precursor. In some embodiments, the resulting perovskite material can have a cubic crystal structure in the bulk material away from the surface. The presence of bulky organic cations near the surface of the perovskite material can result in a non-cubic crystal structure near the surface of the perovskite material.

[0145]

[0178] In another embodiment, the above method can be used with lead (II) iodide solution, cesium iodide solution, methylammonium iodide (MA) salt solution, and benzylammonium salt solution to produce compounds of formula Cs i MA 1-i PbI3 (where i is a number between 0 and 1), a benzylammonium surface layer of perovskite material may be obtained. As another example, lead(II) iodide solution, rubidium iodide solution, formamidinium iodide (FA) salt solution, and benzylammonium salt solution may be used to obtain a perovskite material of the formula Rb i FA 1-i It is possible to obtain a perovskite material with a benzylammonium surface layer of PbI3 (where i is a number between 0 and 1). As another example, lead(II) iodide solution, cesium iodide solution, formamidinium iodide (FA) salt solution, and benzylammonium salt solution can be used to obtain a perovskite material with the formula Cs i FA 1-i It is possible to obtain a perovskite material in which the surface layer of PbI3 (where i is a number between 0 and 1) is benzylammonium. As another example, using a lead(II) iodide solution, a potassium iodide solution, and a formamidinium iodide (FA) salt solution and a benzylammonium salt solution, the perovskite material of the formula K i FA 1-i It is possible to obtain a perovskite material in which the surface layer of PbI3 (where i is a number between 0 and 1) is benzylammonium. As another example, a lead(II) iodide solution, a sodium iodide solution, a formamidinium iodide (FA) salt solution, and a benzylammonium salt solution are used to obtain a perovskite material of the formula Na i FA 1-i It is possible to obtain a perovskite material with a benzylammonium surface layer of PbI3 (where i is a number between 0 and 1). As another example, using a lead(II) iodide-lead(II) chloride mixed solution, a cesium iodide solution, a formamidinium iodide (FA) salt solution, and a benzylammonium salt solution, the perovskite material of the formula Cs i FA 1-i PbI 3-y Cl y(wherein i is a number between 0 and 1, and y is a number between 0 and 3), a perovskite material having a surface layer of benzylammonium can be obtained.

[0146]

[0179] A method for producing perovskite materials using benzylammonium is described below. First, a lead iodide precursor ink is prepared by dissolving PbI2, PbCl2, and cesium iodide (CsI) in a mixture of DMF and DMSO solvents. To prepare the lead iodide precursor, CsI is dissolved in DMSO to prepare a 1.5 M CsI / DMSO solution. In one embodiment, the CsI / DMSO solution can be prepared by stirring 1.5 mmol of CsI per 1.0 mL of anhydrous DMSO in DMSO at room temperature for 1 to 2.5 hours. Next, the above CsI solution is added to a solution of PbI2, PbCl2, and anhydrous DMF solvent to obtain a 1.28 M PbI solution, which has a Cs to Pb ratio of 1:10 and an I to Cl ratio of 9:1. 2+ In one embodiment, a 1.28 M Pb solution is formed. 2+ The solution can be prepared by adding 93.8 μL of CsI solution to a vessel containing 1.26 mmol of PbI, 0.14 mmol of PbCl, and 1.0 mL of anhydrous DMF solvent. 2+ The solution is mixed at a temperature of 50°C to 100°C for 1.5 to 2.5 hours, and then cooled to form a lead iodide precursor ink. 2+ The solution can be stirred at 85°C for 2 hours, followed by cooling by stirring at room temperature for 1 hour. In some embodiments, the lead iodide precursor ink can be filtered prior to deposition of the lead iodide precursor ink. In some embodiments, a 0.2 μm filter can be used to filter the lead iodide precursor ink.

[0147]

[0180] Formamidinium iodide (FAI) and benzylammonium iodide (BzAI) solutions are prepared by dissolving FAI and BzAI salts in anhydrous isopropanol (IPA) to form 0.2 M FAI and 0.05 M BzAI solutions, respectively. In one embodiment, both the FAI and BzAI solutions can be kept at 75° C. during the following coating process.

[0148]

[0181] The lead iodide precursor ink is then deposited on a substrate and annealed to form a lead iodide film. In one embodiment, the lead iodide precursor ink, held at 45° C., can be blade coated onto a substrate coated with a nickel oxide (NiO) thin film layer and then annealed at 50° C. for 10 minutes to form a lead iodide film.

[0149]

[0182] Next, to form a perovskite material layer, the lead iodide film is first primed with a BzAI solution, followed by three coats of FAI solution. After deposition of each coat of BzAI and FAI solution, the coat is allowed to dry before depositing the next coat. In one embodiment, both the BzAI and FAI solutions can be held at 45°C during deposition of each coat. After the third FAI coat is deposited, the substrate and coating can be annealed to form the perovskite material layer. In one embodiment, after the third FAI coat is deposited, the substrate is immediately heated to 157°C for 5 minutes to anneal the perovskite material layer.

[0150]

[0183] The above method may have certain advantages. For example, depositing a BzAI solution on a lead iodide film before the deposition of an FAI solution can provide an intermediate template for the growth of a 3D FAPbI3 perovskite material through the formation of a 2D perovskite material. BzAI can react with the lead iodide thin film to form an intermediate 2D perovskite material phase. When reacted with FAI after the deposition of the FAI solution, BzA+ cations in the 2D phase are completely or partially replaced by FA+ cations, forming a 3D FAPbI3 framework. Furthermore, BzAI can also passivate crystalline defects in the 3D FAPbI3 perovskite material. The photoluminescence intensity of FAPbI3 thin films formed by the above process was shown to be brighter (higher) than that of FAPbI3 thin films formed by a process that did not include BzAI. Figure 31 shows both optical (absorbance) and photoluminescence images of a perovskite material photovoltaic device 3105 produced without the addition of BzAI, and a perovskite material photovoltaic device 3110 produced with BzAI, as described herein. Figure 31 shows that the optical image of perovskite material photovoltaic device 3110 is darker, indicating higher optical absorbance, and that the photoluminescence image of perovskite material photovoltaic device 3110 is brighter than perovskite material photovoltaic device 3105. Furthermore, power output has been observed to be greater from perovskite material photovoltaic devices incorporating BzAI. Figure 32 shows power output curve 3205 corresponding to a photovoltaic device without BzAI, such as photovoltaic device 3105, and power output curve 3210 corresponding to a photovoltaic device including BzAI, as described herein, such as photovoltaic device 3110. The power output measurements shown in Figure 32 are taken at 100 mW / cm to demonstrate steady-state performance. 2 Measurements were taken at the maximum power point under AM1.5G illumination for 180 seconds, with a 30-second intervening dark measurement. As can be seen in Figure 32, the photovoltaic device incorporating BzAI during fabrication produced a significantly higher power output than the photovoltaic device without BzAI (15.0 mW / cm). 2 , 770 mV, and 19.5 mA / cm 2 ) than the power per unit area (16.0 mW / cm2 ) is large (785 mV), and the current per unit area (20.3 mA / cm 2 ) becomes larger. Figure 33 shows current-voltage (IV) scans 3320 of perovskite material photovoltaic devices fabricated without BzAI, labeled as the sample "5r" line, and perovskite material photovoltaic devices fabricated with BzAI, labeled as the sample "10r" line. As can be seen from Figure 33, perovskite material photovoltaic devices fabricated with BzAI produce larger currents over a range of bias voltages than perovskite material photovoltaic devices fabricated without BzAI. Additionally, Figure 34 shows box plots of open circuit voltage, short circuit current density, fill factor, and power conversion efficiency for six perovskite material photovoltaic devices fabricated without BzAI (Sample 5, r = reverse scan, f = forward scan, and s = steady-state measurement) and six perovskite material photovoltaic devices fabricated with BzAI (Sample 10). Figure 35 shows the external quantum efficiency of six perovskite material photovoltaic devices fabricated without BzAI (plot 3505) and six perovskite material photovoltaic devices fabricated with BzAI (plot 3510). Each EQE curve in Figure 35 is expressed in mA / cm 2The spectra are integrated to estimate the Jsc at 1000 K, which shows that perovskite material devices fabricated with BzAI exhibit a higher Jsc (area under the EQE curve) than perovskite material devices fabricated without BzAI. Finally, Figure 36 shows admittance spectroscopy plot 3605 for a perovskite material photovoltaic device fabricated without BzAI, and admittance spectroscopy plot 3610 for a perovskite material photovoltaic device fabricated with BzAI. Admittance spectroscopy plot 3610 shows reduced ion migration for the sample device with benzylammonium compared to admittance spectroscopy plot 3605 for the sample device without benzylammonium. Excessive ion migration is known to have a detrimental effect on the performance and durability of perovskite material devices, and the inclusion of benzylammonium in perovskite material photovoltaic devices shows that device performance and durability can be improved.

[0151]

[0184] Diammonium butane cation-reinforced perovskite The incorporation of 1,4-diammonium butane, or other polyammonium organic compounds described below, into the crystal structure of a perovskite material can improve the properties of the material. In one embodiment, the addition of 1,4-diammonium butane to FAPbI3 perovskite, as described below, can provide a perovskite material with advantageous properties. In some embodiments, 1,4-diammonium butane can be incorporated into perovskite materials that utilize 1,4-diammonium butane salts in place of bulky organic cation salts in the methods described above, and the addition of 1,4-diammonium butane salts (or other organic polyammonium salts described herein) can occur at any step in the perovskite production method in which the addition of bulky organic cation salts is described above. The inclusion of organic cations such as 1,4-diammonium butane in the crystal structure of a perovskite material can result in deviations from the "ideal" stoichiometry of the perovskite materials disclosed herein. For example, due to the inclusion of such organic cations, the perovskite material may have a formula that is either sub-stoichiometric or superstoichiometric with respect to the formula FAPbI described herein. In this case, the general formula of the perovskite material may be represented as CxMyXz, where x, y, and z are real numbers.

[0152]

[0185] In one embodiment, a 1,4-diammonium butane salt solution may be added to a lead halide precursor ink solution prior to deposition. In some embodiments, the 1,4-diammonium butane salt may be added to a lead halide precursor ink solution at a concentration of 0.001 mol % to 50 mol %. In some embodiments, the 1,4-diammonium butane salt may be added to a lead halide precursor ink solution at a concentration of 0.1 mol % to 20 mol %. In some embodiments, the 1,4-diammonium butane salt may be added to a lead halide precursor ink solution at a concentration of 1 mol % to 10 mol %.

[0153]

[0186] In other embodiments, 1,4-diammonium butane salt may be added to the formamidinium iodide salt solution before contacting the formamidinium iodide salt solution with the lead halide precursor thin film as described above. In some embodiments, the 1,4-diammonium butane salt may be added to the formamidinium iodide salt solution at a concentration of 0.001 mol% to 50 mol%. In some embodiments, the 1,4-diammonium butane salt may be added to the formamidinium iodide salt solution at a concentration of 0.1 mol% to 20 mol%. In some embodiments, the 1,4-diammonium butane salt may be added to the formamidinium iodide salt solution at a concentration of 1 mol% to 10 mol%.

[0154]

[0187] In other embodiments, a 1,4-diammonium butane salt precursor solution can be deposited onto the lead halide thin film formed after deposition of the lead halide precursor ink, or onto the perovskite precursor thin film after deposition of the formamidinium salt solution. In some embodiments, the concentration of the 1,4-diammonium butane salt precursor solution can be from 0.001 mol% to 50 mol%. In some embodiments, the concentration of the 1,4-diammonium butane salt precursor solution can be from 0.1 mol% to 20 mol%. In some embodiments, the concentration of the 1,4-diammonium butane salt precursor solution can be from 1 mol% to 10 mol%.

[0155]

[0188] An exemplary method for depositing a perovskite material including 1,4-diammonium butane includes depositing a lead salt precursor on a substrate to form a lead salt thin film, and depositing an organic cation salt precursor including a first organic cation salt on the lead salt thin film to form a perovskite precursor thin film. The lead salt precursor or the organic cation salt precursor may include 1,4-diammonium butane salt, or the 1,4-diammonium butane salt precursor may be deposited on the lead salt thin film or the perovskite precursor thin film. Finally, the substrate and the perovskite precursor thin film may be annealed to form a perovskite material including 1,4-diammonium butane. The lead salt precursor and the organic cation salt precursor may include any of the solutions described herein for producing perovskite thin films.

[0156]

[0189] The distance between ammonium groups in 1,4-diammonium butane is approximately the same as the distance between formamidinium cations in the crystal lattice of formamidinium lead iodide perovskite materials. Therefore, 1,4-diammonium butane can replace two formamidinium ions during the formation of FAPbI3 materials. In other embodiments, other alkyl polyammonium salts can be added to the lead halide precursor ink during the formation of the perovskite material. For example, 1,8-diammonium octane, bis(4-aminobutyl)amine, and tris(4-aminobutyl)amine can be added. Furthermore, polyammonium polycations containing 1,4-diammonium butane can offer the same benefits as the bulky organic cations described above through similar mechanisms.

[0157]

[0190] FIG. 13 is a schematic diagram illustrating the effect that the addition of 1,4-diammonium butane salt during the process of manufacturing a perovskite material may have on the resulting perovskite 7000. As shown in FIG. 13, 1,4-diammonium butane cations 7020 can replace two formamidinium cations 7010 in the perovskite material crystal lattice. In FAPbI3 perovskite, the spacing between the formamidinium cations is approximately 6.35 Å. The length of the 1,4-diammonium butane cations is approximately 6.28 Å, a difference of only 0.07 Å. Therefore, 1,4-diammonium butane cations can be substituted into the perovskite crystal lattice without significantly changing the properties or structure of the perovskite crystal lattice. In some embodiments, the addition of 1,4-diammonium butane cations to a perovskite material can enhance the properties and stability of the perovskite material. The 1,4-diammonium butane cation acts as a rigid structure within the perovskite material, enhancing its structural and chemical durability. For example, in certain embodiments, perovskite materials doped with the 1,4-diammonium butane cation can exhibit superior dry heat stability compared to perovskite materials without the 1,4-diammonium butane cation. Furthermore, perovskite materials doped with the 1,4-diammonium butane cation can exhibit a blue shift in the emission spectrum of the perovskite material. In certain embodiments, the 1,4-diammonium butane cation can be added to a formamidinium salt solution at a concentration of 0 to 20 mol%. In other embodiments, the 1,4-diammonium butane cation can be added to a formamidinium salt solution at a concentration of 1 to 5 mol%. In certain embodiments, the 1,4-diammonium butane cation was added to a formamidinium salt solution at a concentration of 5 mol%.

[0158]

[0191] Experiments have shown that the addition of up to 20% 1,4-diammonium butane to perovskite materials does not significantly shift the lattice constant. Figure 14 shows the X-ray diffraction peaks of perovskite with 0 mol%, 5 mol%, 10 mol%, and 20 mol% 1,4-diammonium butane iodide ("DABI"). The major peaks are at the same positions at each concentration, indicating that the lattice parameters of the perovskite materials do not change significantly with the addition of 1,4-diammonium butane at concentrations between 0 mol% and 20 mol%. The addition of 1,4-diammonium butane results in weakly intense diffraction below 13°2θ with Cu-Kα radiation, indicating a small amount of 2D or layered perovskite phase.

[0159]

[0192] Figure 15 provides images of 0 mol, 1 mol, 2.5 mol%, and 5 mol% perovskite samples exposed to a temperature of 85°C at 0% relative humidity for 7 days. The 0 mol% DABI perovskite material exhibits a significant light color after 1 day and an even more significant yellowing after 7 days. This indicates that the 0 mol% DABI perovskite material has significantly degraded after 1 day of exposure to the test conditions. The 1 mol%, 2.5 mol%, and 5 mol% perovskite material samples all remain dark after 7 days, indicating that the addition of 1 mol% DABI significantly enhances the so-called "dry heat" stability of the perovskite material.

[0160]

[0193] Furthermore, the addition of 1,4-diammoniumbutane to perovskite materials can result in a slight blue shift in the photoluminescence observed in the perovskite materials compared to perovskite materials without 1,4-diammoniumbutane. This blue shift is the result of passivation of trap states within the perovskite materials caused by the addition of 1,4-diammoniumbutane. This blue shift indicates that the addition of 1,4-diammoniumbutane to perovskite materials reduces the defect density in the crystal lattice of the perovskite materials without changing their crystal structure. For example, the resulting blue shift seen in FAPbI3 perovskite material doped with 20 mol% 1,4-diammoniumbutane compared to FAPbI3 perovskite material without 1,4-diammoniumbutane has been observed to be a change of 0.014 eV from 1.538 eV without 1,4-diammoniumbutane to 1.552 eV with 20 mol% 1,4-diammoniumbutane.

[0161]

[0194] In other embodiments, other ammonium complexes can be added during the formation of the perovskite material. For example, Figure 16 shows three ammonium compounds, 1,8-diammoniumoctane, bis(4-aminobutyl)-ammonium, and tris(4-aminobutyl)-ammonium, which can be added to the perovskite material in the same manner as described above for the 1,4-diammoniumbutane cation. 1,8-diammoniumoctane, when introduced during the formation of the perovskite material as described above, can occupy two formamidinium cation ("A site") spaces in the FAPbI3 perovskite material crystal lattice. Bis(4-aminobutyl)-ammonium, when introduced during the formation of the perovskite material as described above, can occupy three A site spaces in the FAPbI3 perovskite material crystal lattice. Tris(4-aminobutyl)-ammonium, when introduced during the formation of the perovskite material as described above, can occupy four A site spaces in the FAPbI3 perovskite material crystal lattice. 16A-16C provide stylized illustrations of the incorporation of three ammonium compounds shown in FIG. 16 into the FAPbI3 perovskite material crystal lattice. FIG. 16A is a stylized illustration of the incorporation of 1,8-diammonium octane into the FAPbI3 perovskite material crystal lattice 7100. As shown in FIG. 16A, 1,8-diammonium octane cations 7120 may replace two formamidinium cations 7110 in the perovskite material crystal lattice. FIG. 16B is a stylized illustration of the incorporation of bis(4-aminobutyl)-ammonium into the FAPbI3 perovskite material crystal lattice 7200. As shown in FIG. 16B, bis(4-aminobutyl)-ammonium cations 7220 may replace three formamidinium cations 7210 in the perovskite material crystal lattice. Figure 16C is a stylized illustration of the incorporation of tris(4-aminobutyl)-ammonium into a FAPbI3 perovskite material crystal lattice 7300. As shown in Figure 16c, tris(4-aminobutyl)-ammonium cations 7320 can replace four formamidinium cations 7310 in the perovskite material crystal lattice.In other embodiments, alkyldiammonium complexes having carbon chains of 2 to 20 carbon atoms can be added to the perovskite material, hi some embodiments, combinations of ammonium complexes can be added to the perovskite material.

[0162]

[0195] Cross-linked interfacial layer In some embodiments, a PV device may include one or more crosslinked interfacial layers. Crosslinked interfacial layers may be physically and chemically more robust than non-crosslinked interfacial layers. For example, crosslinked interfacial layers may be harder, tougher, denser, less permeable to liquids and / or gases, and less reactive than non-crosslinked interfacial layers. Furthermore, crosslinked interfacial layers may have different electrical properties than non-crosslinked interfacial layers. Crosslinked interfacial layers may include dielectric polymers, crosslinked polymers, crosslinked fullerenes, and composites of fullerenes and nanoparticles. In some embodiments, a crosslinked interfacial layer may be deposited as an IFL between an electrode and a photoactive layer, such as IFL 1030 and IFL 1050 in FIG. 1 .

[0163]

[0196] The crosslinked interfacial layer may comprise one or more of a polymer, a fullerene, and a fullerene derivative.

[0164]

[0197] Examples of polymers include:

[0198] Polyvinylarenes, including ortho-, para-, or meta-isomers and di-, tri-, tetra-, and penta-substituted derivatives, as well as polystyrene, polyvinylnaphthalene, polyvinylphenol (e.g., poly(4-vinylphenol)), polyvinylaniline, polyvinylbenzoic acid, polyvinylhaloarenes (e.g., poly(4-chlorostyrene)), polyvinylpyridines (e.g., poly(4-vinylpyridine)), polyvinylthiophene, polyvinylpyrrole, polyvinylfuran, and polyvinylpyrrolidone.

[0165]

[0199] Examples of polyarenes include polyacenaphthylene, polyphenylene oxide, polyphenylene sulfide, polyaniline, polyfuran, polythiophene, and polypyrrole.

[0166]

[0200] Examples of polyvinyl alkanes include polyolefins (e.g., polyethylene, polypropylene, polyacetylene), polyvinyl alcohol, polyvinyl acetate, polyvinyl halide, polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, polyacrylonitrile, polyvinylcyclohexane, polyvinylamine, and polyvinylthiol.

[0167]

[0201] Examples of fullerenes include C60, C70, and C84.

[0168]

[0202] Substituted fullerenes include azafullerene (C60-nnn), borafullerene (C60-nBn), and azabalafullerene (C60-(n+m)NnBm).

[0169]

[0203] As endohedral fullerenes (endofullerenes), metallofullerenes (M@C 60 , M is any transition metal), trimetaspherical carbon nanomaterials (MN@C 80 , M is a lanthanide or any transition metal), M@C 80 (M is any transition metal) and non-metal doped fullerenes (e.g., Ng@C60, Ng=He, Ne, Ar, Kr, Xe (rare gases) and H2@C 60 Examples include endohedral fullerenes (endofullerenes) containing

[0170]

[0204] Exohedral fullerenes include fullerenols (e.g., C 60 (OH) n (n=1 to 60)), alkyl fullerenes (e.g., C 60 Rn (n = 1 to 60)), halofullerenes (e.g., C 60Xn (X=F, Cl, Br, or I, n=1 to 60), hydrofullerenes (e.g., C 60 Hn (n=1-60), methanofullerene derivatives (e.g., dialkyl ester methanofullerenes, including benzyl derivatives (C 60 C(CO2)2 (R = alkyl or aryl group), dialkynylmethanofluorenes (C 60 C(C2R)2), fullerenedihydrolphyrols (C 60 CR2NCCOR), Plato derivatives: C 60 Examples include C2NR (R = alkyl or aryl group phenyl C61)-butyric acid methyl ester (PCMA), phenyl-C61-butyric acid methyl ester (PCMB), transition metal fullerene complexes, and fulleriod(methanoannulene) (open-ring fullerene derivatives).

[0171]

[0205] In one embodiment, the crosslinked interfacial layer may be comprised of fullerenes crosslinked by one or more polymers, such as polystyrene, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), poly(4-vinylphenol), [6,6]-phenyl-C61-butyric acid, or other poly(3-vinylphenol), poly(2-vinylphenol), poly(3,5-dihydroxystyrene), poly(3,4-dihydroxystyrene), and poly(3,4,5-trihydroxystyrene), with poly(4-vinylphenol) and polyvinylaryl substituted.

[0172]

[0206] In one embodiment, the crosslinked interfacial layer may comprise a mixture of polystyrene and silane monomers. As described herein, the silane may include any hydro-, hydroxy-, halo-, alkyl-, alkenyl-, alkynyl-, cyclo-, aromatic-, alkoxyalkyl-, alkoxyalkenyl-, alkoxyaromatic-, haloalkyl-, haloalkenyl-, haloalkyne-, and haloaromatic silane. In other embodiments, boranes, amines, phosphines, dicarboxylic acids, disulfide bonds, and cyclophanes and cyclophane derivatives may be used to crosslink the IFLs instead of silanes. Figure 37 illustrates the pre- and post-crosslinking structures of a crosslinked interfacial layer comprised of polystyrene and a halosilylalkane. In the embodiment shown in Figure 37, 1,6-bis(trichlorosilyl)hexane acts to crosslink the polystyrene polymer molecules in the interfacial layer. However, in other embodiments, any alkane or arene (e.g., benzene) can be substituted for the hexane shown, and any halogen or alkoxy group (e.g., methoxy, ethoxy) can be substituted for the chloro group.

[0173]

[0207] In other embodiments, the crosslinked interfacial layer may comprise a mixture of polystyrene, silane, and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). In other embodiments, instead of silane, boranes, amines, phosphines, dicarboxylic acids, disulfide bonds, and cyclophanes and cyclophane derivatives may be used to crosslink the IFLs. Figure 38 shows the structure of a crosslinked interfacial layer consisting of PCBM, polystyrene, and a halosilylalkane before and after crosslinking. Figure 38 shows an alkylsilane acting to crosslink polystyrene polymer molecules in the interfacial layer while immobilizing PCBM molecules within the crosslinked polymer interfacial layer.

[0174]

[0208] In one embodiment, the crosslinked interfacial layer may comprise a mixture of poly(4-vinylphenol) and silane monomers. In other embodiments, boranes, amines, phosphines, dicarboxylic acids, disulfide bonds, and cyclophanes and cyclophane derivatives may be used in place of silanes to crosslink the IFLs. In other embodiments, poly(3-vinylphenol), poly(2-vinylphenol), poly(3,5-dihydroxystyrene), poly(3,4-dihydroxystyrene), and poly(3,4,5-trihydroxystyrene) are substituted for poly(4-vinylphenol). Figure 39 shows the structure of a crosslinked interfacial layer composed of poly(4-vinylphenol) and a halosilylalkane before and after crosslinking. Figure 39 shows a halosilylalkane acting to crosslink poly(4-vinylphenol) polymer molecules in the interfacial layer.

[0175]

[0209] In other embodiments, the crosslinked interfacial layer may comprise a mixture of poly(4-vinylphenol), silane, and PCBM. In other embodiments, boranes, amines, phosphines, dicarboxylic acids, disulfide bonds, and cyclophanes and cyclophane derivatives may be used in place of silanes to crosslink the IFLs. In other embodiments, poly(3-vinylphenol), poly(2-vinylphenol), poly(3,5-dihydroxystyrene), poly(3,4-dihydroxystyrene), and poly(3,4,5-trihydroxystyrene) are substituted for poly(4-vinylphenol). Figure 40 shows the structure of a crosslinked interfacial layer composed of PCBM, poly(4-vinylphenol), and a halosilylalkane before and after crosslinking. Figure 40 shows the halosilylalkane acting to crosslink poly(4-vinylphenol) polymer molecules in the interfacial layer while immobilizing the PCBM molecules within the crosslinked polymer interfacial layer.

[0176]

[0210] In other embodiments, the crosslinked interfacial layer may comprise a mixture of polystyrene, silane, and [6,6]-phenyl-C61-butyric acid (PCBA). In other embodiments, instead of silane, boranes, amines, phosphines, dicarboxylic acids, disulfide bonds, and cyclophanes and cyclophane derivatives may be used to crosslink the IFL. Figure 41 shows the structure of a crosslinked interfacial layer consisting of PCBA, polystyrene, and a halosilylalkane before and after crosslinking. Figure 41 shows the halosilylalkane acting to crosslink the polystyrene polymer molecules and PCBA molecules in the interfacial layer.

[0177]

[0211] In other embodiments, the crosslinked interfacial layer may comprise a mixture of poly(4-vinylphenol), silane, and PCBA. In other embodiments, borane, amine, phosphine, dicarboxylic acid, disulfide bond, and cyclophane and cyclophane derivatives may be used instead of silane to crosslink the IFL. In other embodiments, poly(3-vinylphenol), poly(2-vinylphenol), poly(3,5-dihydroxystyrene), poly(3,4-dihydroxystyrene), and poly(3,4,5-trihydroxystyrene) are substituted for poly(4-vinylphenol). Figure 42 shows the structure of a crosslinked interfacial layer composed of PCBA, poly(4-vinylphenol), and a halosilylalkane before and after crosslinking. Figure 42 shows the halosilylalkane acting to crosslink the poly(4-vinylphenol) polymer molecules and PCBA molecules in the interfacial layer. As shown in Figure 42, the PCBA molecules are fully immobilized within the crosslinked polymer interfacial layer by binding to the silane groups of the halosilylalkane compound.

[0178]

[0212] A method for depositing a cross-linked fullerene interfacial layer is described below. Initially, cyclophane is converted to dimethylbenzene radicals. The dimethylbenzene radicals are then deposited onto a substrate along with the fullerene, resulting in a cross-linked interfacial layer with the fullerene cross-linked by one or more dimethylbenzene molecules. In some embodiments, the fullerene and dimethylbenzene radicals can be deposited by chemical vapor deposition, vapor deposition, or plasma deposition. When deposited on a perovskite layer, the interfacial layer deposited by this method can form a conformal coating along the surface of the perovskite material. The fullerene and cross-linked dimethylbenzene polymers can randomly pack on the surface of the perovskite, thereby enhancing the degree of contact between the interfacial layer and the perovskite layer.

[0179]

[0213] Another method for depositing a bridged fullerene interfacial layer is described below. First, a fullerene is functionalized with alkyl hydroxide groups on the surface of the fullerene. The functionalized fullerene is then deposited on a substrate. In some embodiments, the functionalized fullerene can be deposited on a perovskite layer of a photovoltaic device. The functionalized fullerene can be deposited by methods including, but not limited to, spin coating, slot die printing, chemical vapor deposition, thermal evaporation, sputtering, atomic layer deposition, extrusion, and gravure printing. The fullerene coating can then be treated with a silane compound to form a bridged silicon-fullerene interfacial layer. The silane compound may include any hydro-, hydroxy-, halo-, alkyl-, alkenyl-, alkynyl-, cyclo-, aromatic-, alkoxylalkyl-, alkoxyalkenyl-, alkoxyaromatic-, haloalkyl-, haloalkenyl-, haloalkynyl-, haloalkyne-, and haloaromatic silane. In other embodiments, instead of silanes, boranes, amines, phosphines, dicarboxylic acids, disulfide bonds, and cyclophanes and cyclophane derivatives can be used to crosslink IFLs. In some embodiments, the silane compound can be a halosilylalkane. In some embodiments, the halosilylalkane can be 1,6-bis(trichlorosilyl)hexane. Such silicon-fullerene crosslinked interfacial layers can have the advantageous electrical properties of fullerenes enhanced by the physical properties of silicon. For example, silicon-fullerene interfacial layers can be water-resistant and flexible while maintaining the desirable electrical properties of fullerenes.

[0180]

[0214] Yet another method for depositing a crosslinked fullerene interfacial layer is described below. First, a polymer is dissolved in a solvent to form a polymer solution. In some embodiments, the solvent used to dissolve the polymer may include alcohols, aryl solvents, chlorinated solvents, ketones, nitriles, alkane solvents, formamides, esters, and combinations thereof. The concentration of the polymer in the solution may range from about 1 μM to about 1 M. In some embodiments, the concentration of the polymer in the solution may range from about 1 mM to about 10 M. Next, fullerenes are added to the polymer solution. In some embodiments, the fullerenes may be added directly to the polymer solution as a solid, or may be first dissolved in a solvent (e.g., benzene, chlorobenzene, dichlorobenzene, toluene, chloroform) and then added to the polymer solution. In some embodiments, the fullerene concentration after addition may range from about 1 μM to about 10 M. In some embodiments, the fullerene concentration in the solution may range from about 1 mM to about 1 M. Next, a crosslinker is added directly to the polymer solution as either a liquid or a solid. In some embodiments, the crosslinker may be dissolved in a solvent and then added to the polymer solution. Solvents used to dissolve the crosslinker may include alcohols, aryl solvents, chlorinated solvents, acetone, acetonitrile, alkyl solvents, formamides, esters, and combinations thereof. In some embodiments, the crosslinker may be added to the polymer solution before the addition of the fullerene. The crosslinker concentration after addition to the fullerene and polymer solution may range from about 1 μM to about 10 M. In some embodiments, the crosslinker concentration in the solution may range from about 1 mM to about 1 M. In some embodiments, the solution may be prepared in a substantially air-free (i.e., oxygen- or water-free) environment, which may avoid premature crosslinking and solidification of the crosslinked interface layer ink. In some embodiments, the crosslinker may be added immediately before application of the crosslinked interface layer ink. The polymer described herein may include any polymer disclosed herein, and the fullerene may include any fullerene or fullerene derivative disclosed herein. Alternatively, the polymer may be added to the fullerene and / or crosslinker solution, as described above.

[0181]

[0215] The crosslinked interfacial layer ink of the present disclosure can be deposited by blade coating, spin coating, slot-die printing, inkjet printing, gravure printing, screen printing, sputtering, spray coating, drop casting, or any other solution-based deposition technique described herein. In embodiments, deposition can occur in ambient, controlled, and / or substantially water-, carbon dioxide-, and oxygen-free atmospheres. The wet layer can be dried ambiently or at elevated temperatures (e.g., 0-250°C). The wet or dried layer can be exposed to UV radiation to promote crosslinking. In some embodiments, the crosslinker may require UV irradiation to crosslink.

[0182]

[0216] The bridged interfacial layer may be deposited directly on the perovskite material layer, on a layer previously deposited on the perovskite layer (e.g., a fullerene, a dielectric material, a semiconductor material, any interfacial layer described in this disclosure), or on a conductive substrate of the present disclosure. When the bridged interfacial layer is deposited on a conductive substrate, the perovskite material may be deposited directly on the bridged interfacial layer, or one or more additional interfacial layers may be deposited on the bridged interfacial layer before the perovskite material is deposited by any of the techniques described herein.

[0183]

[0217] In other embodiments, various different fullerenes, polymers, and cross-linkers can be substituted for the above. For example, Figure 43 shows an example where the fullerene is polyhydroxylfullerene, Figure 44 shows an example where the cross-linker is formaldehyde, and Figure 45 shows an example where the polymer is poly(4-chlorostyrene) and the cross-linker is sodium sulfide.

[0184]

[0218] Thus, the present invention is well adapted to attain the ends and advantages set forth above, as well as the advantages inherent therein. The certain embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, the details of construction or design described herein are not to be limited, except as provided by the appended claims. It is therefore evident that the specific exemplary embodiments disclosed above may be altered or modified, and all such variations are considered to be within the scope and spirit of the present invention. In particular, any range of values ​​disclosed herein (such as "about a to about b," or, equivalently, "about a to b," or, equivalently, "about a to b") are to be understood as referring to a power set (a set of all subsets) of the respective value range, describing all ranges encompassed within the broader range of values. Furthermore, the terms in the claims are to have their plain and ordinary meaning unless expressly and unambiguously defined otherwise by the patentee.

Claims

1. fullerene or fullerene derivative, a cross-linking agent, and one or more polymers, 1. A crosslinked interfacial layer composition comprising:

2. 10. The crosslinked interfacial layer composition of claim 1, wherein the fullerene or fullerene derivative is selected from the group consisting of general fullerenes, substituted fullerenes, endohedral fullerenes, exohedral fullerenes, and any combination thereof.

3. 2. The crosslinked interfacial layer composition of claim 1, wherein the fullerene or fullerene derivative is selected from the group consisting of [6,6]-phenyl-C61-butyric acid methyl ester, [6,6]-phenyl-C61-butyric acid, polyhydroxyl fullerene, and any combination thereof.

4. 10. The crosslinked interfacial layer composition of claim 1, wherein the crosslinking agent is selected from the group consisting of boranes, amines, phosphines, dicarboxylic acids, disulfides, cyclophanes, cyclophane derivatives, formaldehyde, and sodium sulfide.

5. 5. The crosslinked interfacial layer composition of claim 4, wherein the silane is formaldehyde.

6. The crosslinked interfacial layer composition of claim 1 , wherein the one or more polymers comprise a polyvinyl aryl.

7. 10. The crosslinked interfacial layer composition of claim 1, wherein the one or more polymers are selected from the group consisting of 4-(polyvinylphenol), poly(3-vinylphenol), poly(2-vinylphenol), poly(3,5-dihydroxystyrene), poly(3,4-dihydroxystyrene), poly(3,4,5-trihydroxystyrene), poly(4-chlorostyrene), and any combination thereof.

8. 10. The crosslinked interfacial layer composition of claim 1, wherein the one or more polymers are selected from the group consisting of polystyrene, polyvinylnaphthalene, polyvinylphenol, polyvinylaniline, polyvinylbenzoic acid, polyvinylhaloarenes, polyvinylpyridine, polyvinylthiophene, polyvinylpyrrole, polyvinylfuran, polyvinylpyrrolidone, and any combination thereof.

9. 10. The crosslinked interfacial layer composition of claim 1, wherein the one or more polymers are selected from the group consisting of polyacenaphthylene, polyphenylene oxide, polyphenylene sulfide, polyaniline, polyfuran, polythiophene, polypyrrole, and any combination thereof.

10. 10. The crosslinked interfacial layer composition of claim 1, wherein the one or more polymers are selected from the group consisting of polyolefins, polyvinyl alcohols, polyvinyl acetates, polyvinyl halides, polyacrylic acids, polymethacrylates, polymethyl methacrylates, polyacrylonitriles, polyvinyl cyclohexanes, polyvinyl amines, polyvinyl thiols, and any combination thereof.

11. a photoactive material comprising a perovskite material; and fullerene or fullerene derivative, a cross-linking agent, and one or more polymers an interfacial layer comprising a crosslinked polymer, 1. A photovoltaic device comprising:

12. 12. The photovoltaic device of claim 11, wherein the fullerene or fullerene derivative is selected from the group consisting of [6,6]-phenyl-C61-butyric acid methyl ester, [6,6]-phenyl-C61-butyric acid, polyhydroxyl fullerene, and any combination thereof.

13. 12. The photovoltaic device of claim 11, wherein the fullerene or fullerene derivative is selected from the group consisting of general fullerenes, substituted fullerenes, endohedral fullerenes, exohedral fullerenes, and any combination thereof.

14. 12. The photovoltaic device of claim 11, wherein the crosslinking agent is selected from the group consisting of boranes, amines, phosphines, dicarboxylic acids, disulfides, cyclophanes, cyclophane derivatives, formaldehyde, and sodium sulfide.

15. 15. The photovoltaic device of claim 14, wherein the silane is formaldehyde.

16. 12. The photovoltaic device of claim 11, wherein the one or more polymers comprise a polyvinyl aryl.

17. 12. The photovoltaic device of claim 11, wherein the one or more polymers are selected from the group consisting of 4-(polyvinylphenol), poly(3-vinylphenol), poly(2-vinylphenol), poly(3,5-dihydroxystyrene), poly(3,4-dihydroxystyrene), poly(3,4,5-trihydroxystyrene), poly(4-chlorostyrene), and any combination thereof.

18. 12. The photovoltaic device of claim 11, wherein the one or more polymers are selected from the group consisting of polystyrene, polyvinylnaphthalene, polyvinylphenol, polyvinylaniline, polyvinylbenzoic acid, polyvinylhaloarenes, polyvinylpyridine, polyvinylthiophene, polyvinylpyrrole, polyvinylfuran, polyvinylpyrrolidone, and any combination thereof.

19. 12. The photovoltaic device of claim 11, wherein the one or more polymers are selected from the group consisting of polyacenaphthylene, polyphenylene oxide, polyphenylene sulfide, polyaniline, polyfuran, polythiophene, polypyrrole, and any combination thereof.

20. 12. The photovoltaic device of claim 11, wherein the one or more polymers are selected from the group consisting of polyolefins, polyvinyl alcohols, polyvinyl acetates, polyvinyl halides, polyacrylic acids, polymethacrylates, polymethyl methacrylates, polyacrylonitriles, polyvinyl cyclohexanes, polyvinyl amines, polyvinyl thiols, and any combination thereof.

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