Perovskites, acetonitrile / dimethyl sulfoxide-based solvent systems, and methods of use thereof

Abstract

The disclosed subject matter relates to perovskites, acetonitrile / dimethyl sulfoxide-based solvent systems therefor, and methods of use thereof. For example, disclosed herein are double cation perovskites comprising: CsxFA1-xPb(I1-yBry)3. Also disclosed herein are perovskite inks comprising a perovskite, a solvent, and an additive, wherein the additive comprises dodecylammonium iodide (DAI). Also disclosed herein are solvent systems for preparing perovskite films from perovskite inks, the solvent system comprising acetonitrile (ACN) and dimethyl sulfoxide (DMSO). Also disclosed herein are methods of making a perovskite film, comprising pre-treating a substrate with a pretreatment compound comprising phenethylammonium iodide (PEAI), and subsequently depositing a perovskite ink on the pre-treated substrate, wherein the perovskite ink comprises a perovskite and a solvent.

Description

[0001] 10046-679W01: 8683 KOR PEROVSKITES, ACETONITRILE / DIMETHYL SULFOXIDE-BASED SOLVENT SYSTEMS, AND METHODS OF USE THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U. S. Provisional Application No.

[0002] 63 / 779,651 filed March 28, 2025, which is hereby incorporated herein by reference in its entirety.

[0003] STATEMENT OF GOVERNMENT SUPPORT

[0004] This invention was made with government support under EEC2052814 awarded by the National Science Foundation. The government has certain rights in the invention.

[0005] BACKGROUND

[0006] The performance of metal halide perovskite photovoltaic devices has significantly improved in a relatively short timeframe. There is continued optimism that perovskite solar cells (PSCs) will become commercially and widely available in the near future, offering solar cell materials that are suitable for low-cost and high-efficiency tandem cells, flexible devices, and low-temperature, high-throughput manufacturing. One area of concern that should be addressed before the commercialization of PSCs is the toxicity and environmental impacts of the solvents used, while maintaining uniformity and quality of large-scale deposition of perovskite materials, especially onto topographically complex surfaces. The compositions, devices, and methods discussed herein address these and other needs.

[0007] SUMMARY

[0008] In accordance with the purposes of the disclosed compositions, methods, and systems as embodied and broadly described herein, the disclosed subject matter relates to perovskites, acetonitrile / dimethyl sulfoxide -based solvent systems therefor, and methods of use thereof. For example, disclosed herein are ambient-processable acetonitrile / dimethyl sulfoxide-based microgroove perovskite photovoltaic devices.

[0009] For example, disclosed herein are double cation perovskites comprising: CsxFA1-xPb(I1-yBry)3, where FA is formamidinium; x is from greater than 0 to less than 1; and y is from greater than 0 to less than 1.

[0010] In some examples, the double cation perovskite is substantially free of

[0011] methyl ammonium.

[0012] In some examples, the double cation perovskite consists essentially of CsxFA1-xPb(I1-yBry)3.

[0013] In some examples, the double cation perovskite consists of CsxFA1-xPb(I1-yBry)3.

[0014] In some examples, x is from 0.05 to 0.1.In some examples, x is 0.05, 0.07, 0.1, or 0.15.

[0015] In some examples, x is 0.1.

[0016] In some examples, y is 0.05.

[0017] In some examples, x is from 0.05 to 0.15 and y is 0.05.

[0018] In some examples, x is 0.05, 0.07, 0.1, or 0.15 and wherein y is 0.05.

[0019] In some examples, the double cation perovskite comprises Cso.iFAo.9Pb(Io.95Bro.o5)3. In some examples, the double cation perovskite comprises Cso.iFAo.9Pb(Io.95Bro.o5)3 and is substantially free of methylammonium.

[0020] In some examples, the double cation perovskite consists essentially of Cso.iFAo.9Pb(Io.95Bro.o5)3.

[0021] In some examples, the double cation perovskite consists of Cso.iFAo.9Pb(Io.95Bro.o5)3. Also disclosed herein are inks comprising any of the perovskites disclosed herein and a solvent.

[0022] In some examples, the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0023] In some examples, the solvent comprises any of the solvent systems disclosed herein. In some examples, the ink further comprises an additive.

[0024] In some examples, the additive comprises dodecylammonium iodide (DAI).

[0025] In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0026] In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0027] Also disclosed herein are perovskite inks comprising a perovskite, a solvent, and an additive, wherein the additive comprises dodecylammonium iodide (DAI).

[0028] In some examples, the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0029] In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0030] In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a10046-679W01: 8683 KOR photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0031] In some examples, the perovskite comprises a double cation perovskite. In some examples, the cations comprise FA and Cs.

[0032] In some examples, the perovskite is substantially free of methylammonium.

[0033] In some examples, the perovskite is a multi-halide perovskite. In some examples, the halides comprise I and Br.

[0034] In some examples, the perovskite is any of the perovskites disclosed herein.

[0035] In some examples, the solvent comprises any of the solvent systems disclosed herein. Also disclosed herein are solvent systems for preparing perovskite films from perovskite inks, the solvent system comprising acetonitrile (ACN) and dimethyl sulfoxide (DMSO).

[0036] In some examples, the DMSO is a coordinating solvent to dissolve the perovskite and acetonitrile is a diluting solvent.

[0037] In some examples, the solvent system is substantially free of methylamine.

[0038] In some examples, the solvent system comprises ACN in an amount of from greater than 0 to less than 100 % (v / v), based on the total volume of ACN and DMSO.

[0039] In some examples, the solvent system comprises ACN in an amount of from 50 to 83.3% (v / v), such as from 50 to 75% (v / v), such as 66% (v / v), based on the total volume of ACN and DMSO.

[0040] In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN: DMSO) of from 10:1 to 1:10.

[0041] In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN: DMSO) of from 5:1 to 1:1, such as from 3:1 to 1:1, such as 2:1.

[0042] In some examples, the solvent system consists essentially of acetonitrile and dimethyl sulfoxide (DMSO).

[0043] In some examples, the solvent system consists of acetonitrile and dimethyl sulfoxide (DMSO).

[0044] Also disclosed herein are inks comprising a perovskite and any of the solvent systems disclosed herein.

[0045] In some examples, the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0046] In some examples, the perovskite comprises a double cation perovskite. In some10046-679W01: 8683 KOR examples, the cations comprise FA and Cs.

[0047] In some examples, the perovskite is substantially free of methylammonium.

[0048] In some examples, the perovskite is a multi-halide perovskite. In some examples, the halides comprise I and Br.

[0049] In some examples, the perovskite is any of the perovskites disclosed herein.

[0050] In some examples, the ink further comprises an additive.

[0051] In some examples, the additive comprises dodecylammonium iodide (DAI).

[0052] In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0053] In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0054] In some examples, the ink is ambient processable.

[0055] In some examples, the ink is less toxic than a similar ink comprising conventional perovskite ink processing solvents.

[0056] In some examples, the ink is greener than a similar ink comprising conventional perovskite ink processing solvents.

[0057] In some examples, the ink is compatible with blade coating, such as air knife-assisted ambient blade coating.

[0058] In some examples, the ink is compatible with roll-to-roll processing.

[0059] In some examples, the ink is compatible with flexible substrates.

[0060] In some examples, the ink is compatible with flexible microgroove substrates, such as those described in Blackburn et al. ACS Applied Energy Materials, 2025, 8(4), 2219-2228; Pernik et al. 2016, ACS Energy Letters, 1(5), 1021-1027; Wong-Stringer et al. 2019, Energy and Environmental Science, 2019, 12(6), 1928–1937; WO 2014 / 118545 and / or WO 2012 / 175902.

[0061] In some examples, the ink is capable of preparing a perovskite film on a substrate, such as the flexible microgroove substrate, that is substantially more uniform relative to a film prepared using conventional perovskite ink processing solvents.

[0062] Also disclosed herein are methods of making a perovskite film, comprising depositing a perovskite ink on a substrate, wherein the perovskite ink comprises a perovskite and a solvent, wherein the perovskite is any of the perovskites disclosed herein, the solvent is any of the10046-679W01: 8683 KOR solvent systems disclosed herein, the perovskite ink is any of those disclosed herein, or a combination thereof.

[0063] In some examples, the perovskite is any of the perovskites disclosed herein.

[0064] In some examples, the solvent is any of the solvent systems disclosed herein.

[0065] In some examples, the perovskite is any of the perovskites disclosed herein and the solvent is any of the solvent systems disclosed herein.

[0066] In some examples, the perovskite ink is any of those disclosed herein.

[0067] In some examples, the perovskite ink further comprises an additive.

[0068] In some examples, the additive comprises dodecylammonium iodide (DAI).

[0069] In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0070] In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0071] In some examples, the method further comprises pre-treating the substrate before depositing the perovskite ink.

[0072] In some examples, pre-treating comprises depositing a pre-treatment compound onto the substrate before depositing the perovskite ink.

[0073] In some examples, the pre-treatment compound modifies the surface energy of the substrate, for example by optimizing the surface Fermi level, passivating at least a portion of the surface to reduce defect density, improving wettability, or a combination thereof.

[0074] In some examples, the pre-treatment compound comprises phenethylammonium iodide (PEAI).

[0075] Also disclosed herein are methods of making a perovskite film, comprising pre-treating a substrate with a pretreatment compound comprising phenethylammonium iodide (PEAT), and subsequently depositing a perovskite ink on the pre-treated substrate, wherein the perovskite ink comprises a perovskite and a solvent.

[0076] In some examples, pre-treating comprises depositing the pre-treatment compound onto the substrate before depositing the perovskite ink.

[0077] In some examples, the pre-treatment compound modifies the surface energy of the substrate, for example by optimizing the surface Fermi level, passivating at least a portion of the10046-679W01: 8683 KOR surface to reduce defect density, improving wettability, or a combination thereof.

[0078] In some examples, the perovskite comprises a double cation perovskite. In some examples, the cations comprise FA and Cs.

[0079] In some examples, the perovskite is substantially free of methylammonium.

[0080] In some examples, the perovskite is a multi-halide perovskite. In some examples, the halides comprise I and Br.

[0081] In some examples, the perovskite is any of the perovskites disclosed herein.

[0082] In some examples, the solvent is any of the solvent systems disclosed herein.

[0083] In some examples, the perovskite is any of the perovskites disclosed herein and the solvent is any of the solvent systems disclosed herein.

[0084] In some examples, the perovskite ink is any of those disclosed herein.

[0085] In some examples, the perovskite ink further comprises an additive.

[0086] In some examples, the additive comprises dodecylammonium iodide (DAI).

[0087] In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0088] In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0089] In some examples, the substrate is rigid.

[0090] In some examples, the substrate comprises glass and / or silicon.

[0091] In some examples, the substrate is flexible.

[0092] In some examples, the substrate is flexible and comprises a polymer, such as an acrylic polymer, polyethylene terephthalate, or a combination thereof.

[0093] In some examples, the substrate is substantially flat.

[0094] In some examples, the substrate is grooved, such as with microgrooves.

[0095] In some examples, the substrate is a flexible microgroove substrate, such as those described in Blackburn et al. ACS Applied Energy Materials, 2025, 8(4), 2219-2228; Pemik et al. 2016, ACS Energy Letters, 1(5), 1021-1027; Wong-Stringer et al. 2019, Energy and Environmental Science, 2019, 12(6), 1928–1937; WO 2014 / 118545 and / or WO 2012 / 175902.

[0096] In some examples, depositing comprises spin coating, blade coating, slot-die coating, gravure coating, chemical bath / vapor deposition, roll-to-roll processing, spray coating, or a10046-679W01: 8683 KOR combination thereof.

[0097] In some examples, depositing comprises blade coating, slot-die coating, gravure coating, chemical bath / vapor deposition, roll-to-roll processing, or a combination thereof.

[0098] In some examples, depositing comprises blade coating, such as air knife-assisted ambient blade coating.

[0099] In some examples, depositing comprises roll-to-roll processing.

[0100] In some examples, the method is performed at ambient conditions.

[0101] Also disclosed herein are perovskite films made by any of the methods disclosed herein. In some examples, the film comprises the perovskite as a-phase.

[0102] Also disclosed herein are methods of use of any of the perovskite films made by any of the methods disclosed herein.

[0103] In some examples, the method comprises using the film in a photovoltaic device, such as a solar cell.

[0104] In some examples, the method comprises using the film for sensing, for catalysis, in a battery, in a LED, or a combination thereof.

[0105] Also disclosed herein are articles of manufacture comprising any of the perovskite films made by any of the methods disclosed herein.

[0106] In some examples, the article is a photovoltaic device, such as a solar cell.

[0107] In some examples, the article is a battery, LED, or a combination thereof.

[0108] Also disclosed herein are photovoltaic devices comprising any of the perovskite films made by any of the methods disclosed herein.

[0109] In some examples, the photovoltaic device is a solar cell.

[0110] Additional advantages of the disclosed compositions, systems, and methods will be set forth in part in the description which follows, and in part will be obvious from the description. The advantages of the disclosed compositions, systems, and methods will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosed compositions, systems, and methods, as claimed.

[0111] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

[0112] BRIEF DESCRIPTION OF THE FIGURES

[0113] The accompanying figures, which are incorporated in and constitute a part of this10046-679W01: 8683 KOR specification, illustrate several aspects of the disclosure, and together with the description, serve to explain the principles of the disclosure.

[0114] Figure 1. Perovskite microgroove photovoltaics for cost-effective roll-to-roll production of flexible solar cells.

[0115] Figure 2. Perovskite microgroove photovoltaics for cost-effective roll-to-roll production of flexible solar cells.

[0116] Figure 3. Towards Scalability.

[0117] Figure 4. Blade coating phenethylammonium iodide (PEAI) as pretreatment increased the PCE by a factor of 5.

[0118] Figure 5. Pretreatment improves groove fill.

[0119] Figure 6. Active layer material and deposition optimization.

[0120] Figure 7. Blade coating improves groove fill.

[0121] Figure 8. Blade coating improves groove fill and leads to higher PCE.

[0122] Figure 9. LaP devices retained 51% PCE after 8 months.

[0123] Figure 10. Barrier film alone retained 12% PCE after 8 months.

[0124] Figure 11. Plastic Solar Cells with Back Contact Microgroove Architecture and Multi¬ Cation Perovskite Absorber.

[0125] Figure 12. Plastic solar cells with perovskite absorber material integrated into a microgroove cascade design, (a) Photograph of a roll of flexible PET substrate embossed with aligned microgrooves that are 1.5 micrometers wide, (b) Top-down SEM image of the microgroove-patterned PET substrate with electron and hole transport layers deposited on opposing sidewalls of the grooves, as shown in (c). The ETL is composed of fullerene (C60) and tin oxide (SnOx) and the HTL is composed of nickel oxide (NiOx). The microgrooves are electrically connected in series, as shown in (d).

[0126] Figure 13: XRD of (a) CsxFA1-xPbI3and (b) CsxFA1-xPb(I0.95Br0.05)3thin films using Cu Kα (λ=1.54 Å) radiation. The addition of 5% Br stabilizes the perovskite phase. Reference patterns are provided for cubic a-FAPbh (PFD# 00-069-0999), hexagonal 8-phase FAPbh, and Pbh peaks are indexed with black lines, blue lines, and red “#” respectively.

[0127] Figure 14. Boxplots of (a) open circuit voltage (Voc), (b) short circuit current density (Jsc), (c) fill factor (FF), and (d) power conversion efficiency (PCE) for a total of 30 microgroove solar cells where each 10 devices are fabricated with either (CH3NH3)PbI3(MAPI), Cs0.1FA0.9Pb(I0.95Br0.05)3(CsFA, double cation), or Cs0.05FA0.79MA0.16Pb(I0.85Br0.15)3(CsFAMA, triple cation) perovskites.

[0128] Figure 15. Absorptance and PL spectra of (CH3NH3)PbI3(MAPI),10046-679W01: 8683 KOR Cs0.1FA0.9Pb(I0.95Br0.05)3(CsFA, double cation), and Cs0.05FA0.79MA0.16Pb(I0.85Br0.15)3(CsFAMA, triple cation) perovskite thin films prepared on glass substrates, with an excitation wavelength (λexc) of 532 nm. Time-resolved photoluminescence (TRPL) data are measured using a pulsed laser spectrometer with λxc=532 nm and shown in the inset, fit to Eqn (1) to determine the PL lifetime of each material.

[0129] Figure 16. SEM images of (a,d) (CH3NH3)PbI3(MAPI), (b,e) Cs0.1FA0.9Pb(I0.95Br0.05)3(CsFA, double cation), and (c,f) Cs0.05FA0.79MA0.16Pb(I0.85Br0.15)3(CsFAMA, triple cation) perovskite thin films on micro-groove solar cells. A few pinhole formations and cracks in the films are highlighted by the black circles and white squares, respectively.

[0130] Figure 17. The water contact angles of different perovskite films.

[0131] Figure 18. Non-ambient aging XRD with temperatures ranging from 30°C to 450 °C under vacuum for different perovskite films.

[0132] Figure 19. (a) XRD patterns of different perovskite thin films using Cu Ka (A=1.54 A) radiation. A reference pattern for tetragonal MAPbb (PFD# 00-068-0701) with peak labels in black is for indexing based on the reference pattern. Perovskite a-phase CsxFAyMAi-x-yPb(InBri-n)3 and Pbb (001) peaks are labeled with blue * and red #, respectively, (b) Enlarged XRD pattern showing the (110) peak shift for different perovskite films.

[0133] Figure 20. Influence of PEAI treatment on device performance and microgroove filling, (a) Variation in Voc and JSc of CsFA devices fabricated with increasing amounts of PEAI treatment. PEAI in ACN (0.12 M) solution is spin-coated on the devices, then annealed at 100 °C for 5 minutes to dry. Two different treatment orders are studied: (•) pre -treat and (■) post-treat. SEM images of cross-sectioned devices showing the uniformity of the perovskite layer in the microgrooves (c) with and (b) without treatment of the device substrates with PEAI before depositing the perovskite layer.

[0134] Figure 21: Optical band gaps, Eg, determined from Tauc plots of the optical absorption of (a) (CH3NH3)PbI3(MAPI), double cation Cs0.1FA0.9Pb(I0.95Br0.05)3(CsFA), and triple cation Cs0.05FA0.79MA0.16Pb(I0.85Br0.15)3(CsFAMA) perovskite films prepared on glass substrate, (d) Band alignment between electron and hole transport layers and the various perovskites studied here.

[0135] Figure 22: SEM images of (a) MAPbI3, (b) double cation Cs0.1FA0.9Pb(I0.95Br0.05)3, and (c) triple cation Cs0.05FA0.79MA0.16Pb(I0.85Br0.15)3perovskite films deposited on microgroove solar cells. Voids in the perovskite layers are identified using ImageJ software and highlighted in red.

[0136] Figure 23: SEM images of (a) MAPbI3, (b) double cation Cs0.1FA0.9Pb(I0.95 / Br0.05)3, and10046-679W01: 8683 KOR (c) triple cation Cs0.05FA0.79MA0.16Pb(I0.85 / Br0.15)3perovskite thin films on micro-groove solar cells. Grain boundaries are outlined in white. Crystal grain size was determined using ImageJ software.

[0137] Figure 24: XRD patterns of Cs0.1FA0.9Pb(I0.95Br0.05)3 films within 9 months of exposure to air at an average room temperature of 25°C and 30% RH.

[0138] Figure 25: Non-ambient aging XRD with temperatures ranging from 30°C to 450 °C under vacuum for different perovskite films.

[0139] Figure 26: Photographs of MAPbI3and Cs0.1FA0.9Pb(I0.95 / Br0.05)3films deposited on 25 mm x 25 mm glass substrates and heated at 210 °C in air for 0 min, 10 min, 40 min, and 75 min.

[0140] Figure 27: Photoluminescence emission (PL) spectra of CsxFA1-xPb(I1-yBry)3perovskite films of varying composition, x prepared on glass substrate (λexc= 625nm).

[0141] Figure 28: (A) SEM image of a PET substrate patterned with a microgroove with EDS maps of (B) carbon, (C) nickel, (D) titanium, (E) oxygen, and (F) tin.

[0142] Figure 29: The water contact angles of a bare PET substrate patterned with microgrooves (a) before and (b) after PEAI treatment.

[0143] Figure 30. Current density-voltage (J-V) curves from 8 devices with Cs0.1FA0.9Pb(I0.95 / Br0.05)3films measured in the forward scan (FS) and reverse scan (RS) directions under simulated AM 1.5G illumination. The inset is an architecture of planar n-i-p solar cell.

[0144] Figure 31. Schematic of the (a) chemical structures and fabrication process of Cs0.1FA0.9Pb(I0.95Br0.05)3perovskite films with dodecyl ammonium iodide (n-DAI) additive, (b) microgroove device embossed into a PET substrate with electron and hole transport layers shadow-deposited on opposing side walls, and (c) blade coating perovskite into these microgroove devices.

[0145] Figure 32. SEM images and grain size distribution of Cs0.1FA0.9Pb(I0.95Br0.05)3perovskite films spin coated on glass with different concentrations of dodecyl ammonium iodide (DAI) additive; (a) 0 mg / mL, (b) 0.2 mg / mL, (c) 1 mg / mL, (d) 2 mg / mL, (e) 5 mg / mL, and (f) 10 mg / mL. Crystal grain size was determined using ImageJ software.

[0146] Figure 33. XRD patterns of (a) Cs0.1FA0.9Pb(I0.95Br0.05)3perovskite thin films with different concentrations of dodecyl ammonium iodide (DAI) additive using Cu Kα (λ= 1.54 Å) radiation and (b) (100) lattice plane of FAPbI3. Reference patterns are provided for cubic α-FAPbI3(PDF# 00-069-0999), hexagonal δ-phase FAPbI3, and PbI2peaks are indexed with black, blue, and orange lines respectively.

[0147] Figure 34. PL, spectra of Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite films spin coated on glass10046-679W01: 8683 KOR with different concentrations of dodecyl ammonium iodide (DAI) additive; with an excitation wavelength ( exc ) of 532 nm.

[0148] Figure 35. N1sXPS spectra of perovskite films with and without DAI additive (a) before and (b) after sputtering with argon; C(=NH)-NH2+(400.8 eV) and R-NH3+(402.3 eV).

[0149] Figure 36. Schematic diagram of the perovskite structure (A) pristine, (B) with dodecyl ammonium iodide (DAI) additive, and (C) after sputtering and removal of adventitious carbon (AdC) and DAI.

[0150] Figure 37. The water contact angles of perovskite films with different concentrations of dodecyl ammonium iodide (DAI) additive.

[0151] Figure 38. Boxplots of power conversion efficiency (PCE) for a total of 146 microgroove solar cells fabricated with Cso.iFAo.9Pb(Io.95Bro.os)3 perovskite with different concentrations of dodecyl ammonium iodide (DAI) additive. Boxes indicate the interquartile range with the median marked; whiskers represent 1.5×IQR.

[0152] Figure 39. SEM images and grain size distribution of control Cso.iFAo.9Pb(Io.95Bro.os)3 perovskite films (a) spin coated on glass and (b) blade coated on PET substrates with microgrooves. Crystal grain size was determined using ImageJ software.

[0153] Figure 40. (a) Architecture of planar n-i-p PSCs, (b & c) Current density- voltage (J-V) curves from devices with or without the optimized DAI additive concentration (2 mg / mL), measured in the forward scan (FS) and reverse scan (RS) directions under simulated AM 1.5G illumination, and (d) Stabilized photocurrent measurement at a bias voltage of maximum power point.

[0154] Figure 41. The molecular structure of dodecyl ammonium iodide (DAI).

[0155] Figure 42. (a) Absorbance spectra and (b) Tauc plots for perovskite films with and without DAI additive.

[0156] Figure 43. XPS spectra of N Is, I 3d, Pb 4f, C 1 s, Cs 3d, and Be 3d for perovskite films with and without DAI additive before (BS) and after (AS) sputtering.

[0157] Figure 44. Boxplots of photovoltaic parameters (a) power conversion efficiency (PCE), (b) open circuit voltage (Voc), (c) short circuit current density (Jsc), and (d) fill factor (FF) for a total of 146 microgroove solar cells fabricated with Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite with different concentrations of dodecyl ammonium iodide (DAI) additive.

[0158] Figure 45. (a) Current density -voltage (J-V) curves and (b) Histogram of efficiency statistics of 22 devices each with or without the optimized DAI additive concentration (2 mg / mL), measured in the reverse scan directions under simulated AM 1.5G illumination.

[0159] Figure 46. Surface optical images of Cso.iFAo.9Pb(Io.95Bro.o5) perovskite films spin10046-679W01: 8683 KOR coated on 25 mm x 25 mm glass substrates and heated at 210 °C in air for 0 min, 25 min, 35 min, 45 min, and 105 min.

[0160] Figure 47. Non-ambient aging XRD of Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite films with and without DAI additive under nitrogen at temperature 210°C.

[0161] Figure 48. XRD patterns of Cso.iFAo.9Pb(Io.95Bro.os)3 perovskite films with and without DAI additive under exposure to air at an average room temperature of 25 °C and 30% RH.

[0162] Figure 49. (a,b) XRD patterns of Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite films with and without DAI additive aged at temperature of 50°C and 50% RH, with the corresponding (c) ratio of perovskite peak (110) to the ratio of emerging lead iodide in the films.

[0163] Figure 50. Acetonitrile / DMSO Perovskite Ink for Ambient Blade Coating on Flexible Photovoltaics.

[0164] Figure 51. (a) Solubility trials on precursor salts dissolved in candidate solvents at 0.6M concentration, (b) Dilutions of Cso.iFAo.9Pb(Io.95Bro.o5)3 in DMSO with various cosolvents with the volume fraction, v / v (%), of the cosolvent and ink concentration, in molarity, shown, (c) Schematic of microgroove substrate blade coating process and films coated with various ink concentrations (M). (d) Vapor pressure vs. viscosity of relevant solvent properties, (e) Plot of ACN / DMSO ink volume percentage and concentrations studied in this work with the champion device performance obtained with ink mixture denoted with a star.

[0165] Figure 52. (a) UV-vis absorbance (black) and PL spectroscopy (blue) of Cso.iFAo.9Pb(Io.95Bro.o5)3 film deposited on glass, (b) XRD spectra of Cso.iFAo.9Pb(Io.95Bro.o5)3 film deposited on microgroove substrate. All data shown is using the ACN / DMSO solvent system. Reference stick pattern for α-FAPbI3(PDF #00-069-0999) is shown in purple with corresponding peak indices labeled. δ-FAPbI3(100) diffraction peak is labeled in magenta.

[0166] Figure 53. (a) Microgroove substrates coated with Cso.iFAo.9Pb(Io.95Bro.o5)3 using ACN / DMSO solvent system on a checkered background to highlight transparency of devices coated at different blade speeds (16, 33, and 50 mm / s). Top-down SEM images of devices coated at 16, 33, and 50 mm / s are shown in (b-d), respectively, (e) JV plots for a single groove cascade from each device with forward and reverse sweeps. Cross-sectional SEM images for the devices coated at 16 mm / s and 50 mm / s are shown in (f).

[0167] Figure 54. (a) Schematic representation of air knife assisted solvent evaporation during the blade coating process of perovskite ink onto microgroove substrates, (b) Pxy diagram generated from Aspen Plus using UNIFAC method and (c) the viscosity as a function of ACN mole fraction (xACN) of a binary ACN / DMSO mixture, (d-g) Large area SEM images show the coating uniformity from increasing air knife exposure with corresponding images at higher10046-679W01: 8683 KOR magnification shown in (h-k) which highlight the overfilling of the grooves. Optimal air knife exposure is seen in (f) and (j), where overfilling across groove walls does not occur.

[0168] Figure 55. JV data and performance metrics of champion device measured under 1 sun simulated light.

[0169] Figure 56. Photographs showing solubility trials of individual precursor salts in Gyrene, anisole, 2ME-THF, and GVL at 0.6 M, 1.0 M, and 1.2 M concentrations.

[0170] Figure 57. Tauc plot of Cs0.1FA0.9Pb(I0.95Br0.05)3film on glass.

[0171] Figure 58. (a) Box plots of forward scan PCE values (%) for several samples coated at nDAI concentrations of 0.0, 0.2, 0.5, and 0.8 mg / mL in the precursor ink. A sample that was pre-treated (PT) with nDAI is also shown, (b) Plots showing device performance metrics including PCE, Voc, Jsc, and FF as a function of nDAI additive concentration.

[0172] Figure 59. Groove Fill Drives Solvent Based Performance Differences in Microgroove Array Photo voltaics.

[0173] Figure 60. a) Photovoltaic performance of microgroove devices fabricated with different solvents b) short circuit currents of devices c) open circuit voltages of devices

[0174] Figure 61. a) Photoluminescence lifetimes of MAPI films with different solvents b) Steady state photoluminescence of MAPI films with different solvents

[0175] Figure 62. Top-Down Scanning Electron Microscopy Images of Perovskite Inks in different Solvents Deposited onto Microgroove Devices.

[0176] Figure 63. X-Ray Diffraction of MAPbh films deposited from different solvents.

[0177] Figure 64. b) contact angle of DMF on electron transport layer c) contact angle of DMF on hole transport layer d) cross sectional SEM of methylamine / acetonitrile based perovskite films e) contact angle of methylamine / acetonitrile on electron transport layer f) contact angle of methylamine acetonitrile on hole transport layer h) contact angle of γ-valerolactone on electron transport layer i) contact angle of γ-valerolactone on hole transport layer.

[0178] Figure 65. a,b) contact angle of DMF on electron transport layer, hole transport layer c,d) contact angle of 9: 1 v:v solution of DMF: DMSO on electron transport layer, hole transport layer e,f) contact angle of a 1:1 v:v solution of DMF: DMSO on electron transport layer, hole transport layer g,h) contact angle of a 1:9 v:v solution of DMF: DMSO on electron transport layer, hole transport layer i,j) contact angle of DMSO on electron transport layer, hole transport layer.

[0179] Figure 66. Aging (50°C and 50 RH%) of Cso.iFAo.9Pb(Io.95Bro.o5)3 films with 2 mg / mL DAI or without.

[0180] Figure 67. Ratio of perovskite peak vs lead peak formation during aging (50°C and 50 RH%) of Cso.iFAo.9Pb(Io.95Bro.o5)3 films with 2 mg / mL DAI or without.10046-679W01: 8683 KOR DETAILED DESCRIPTION

[0181] Before the present compositions, methods, and systems are disclosed and described, it is to be understood that the aspects described below are not limited to specific synthetic methods or specific reagents, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0182] Also, throughout this specification, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which the disclosed matter pertains. The references disclosed are also individually and specifically incorporated by reference herein for the material contained in them that is discussed in the sentence in which the reference is relied upon.

[0183] In this specification and in the claims that follow, reference will be made to a number of terms, which shall be defined to have the following meanings.

[0184] Throughout the description and claims of this specification the word “comprise” and other forms of the word, such as “comprising” and “comprises,” means including but not limited to, and is not intended to exclude, for example, other additives, components, integers, or steps. As used in the specification and in the claims, the term “comprising” can include the aspects “consisting of” and “consisting essentially of.”

[0185] As used in the description and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a composition” includes mixtures of two or more such compositions, reference to “an agent” includes mixtures of two or more such agents, reference to “the component” includes mixtures of two or more such components, and the like.

[0186] “Optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0187] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. By “about” is meant within 5% of the value, e.g., within 4, 3, 2, or 1% of the value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.10046-679W01: 8683 KOR “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal embodiment. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0188] Values can be expressed herein as an “average” value. “Average” generally refers to the statistical mean value.

[0189] By “substantially” is meant within 5%, e.g., within 4%, 3%, 2%, or 1%.

[0190] It is understood that throughout this specification the identifiers “first” and “second” are used solely to aid in distinguishing the various components and steps of the disclosed subject matter. The identifiers “first” and “second” are not intended to imply any particular order, amount, preference, or importance to the components or steps modified by these terms.

[0191] References in the specification and concluding claims to parts by weight of a particular element or component in a composition denotes the weight relationship between the element or component and any other elements or components in the composition or article for which a part by weight is expressed. Thus, in a compound containing 2 parts by weight of component X and 5 parts by weight component Y, X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound.

[0192] A weight percent (wt. %) of a component, unless specifically stated to the contrary, is based on the total weight of the formulation or composition in which the component is included.

[0193] The term “or combinations thereof’ as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.

[0194] Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

[0195] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0196] Compositions, Systems, and Methods

[0197] Disclosed herein are compositions, systems, and methods. For example, disclosed herein are perovskites, acetonitrile / dimethyl sulfoxide-based solvent systems therefor, and methods of use thereof. For example, disclosed herein are compositions, systems, and methods for ambient- processable acetonitrile / dimethyl sulfoxide-based microgroove perovskite photovoltaic devices.10046-679W01: 8683 KOR Perovskites and Inks based thereon

[0198] For example, disclosed herein are double cation perovskites comprising CsxFAi-xPb(Ii-yBry)3, where FA is formamidinium; x is from greater than 0 to less than 1; and y is from greater than 0 to less than 1. In some examples, the double cation perovskite is substantially free of methyl ammonium.

[0199] In some examples, the double cation perovskite consists essentially of CsxFAixPb(Ii.yBry)3. In some examples, the double cation perovskite consists of CsxFAi-xPb(Ii-yBry)3.

[0200] In some examples of CsxFA1-xPb(I1-yBry)3, x is greater than 0 (e.g., 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.1 or more, 0.11 or more, 0.12. or more, 0.13 or more, 0.14 or more, 0.15 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, 0.4 or more, 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more, 0.65 or more, 0.7 or more, 0.75 or more, 0.8 or more, 0.85 or more, 0.9 or more, or 0.95 or more). In some examples of CsxFA1-xPb(I1-yBry)3, x is 0.05 or more. In some examples of CsxFA1-xPb(I1-yBry)3, x is 0.1 or more. In some examples of CsxFA1-xPb(I1-yBry)3, x is less than 1 (e.g., 0.95 or less, 0.9 or less, 0.85 or less, 0.8 or less, 0.75 or less, 0.7 or less, 0.65 or less, 0.6 or less, 0.55 or less, 0.5 or less, 0.45 or less, 0.4 or less, 0.35 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, 0.14 or less, 0.13 or less, 0.12 or less, 0.11 or less, 0.1 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, 0.04 or less, 0.03 or less, 0.02 or less, or 0.01 or less). In some examples of CsxFA1-xPb(I1-yBry)3, x is 0.1 or less. The value of x in CsxFA1-xPb(I1-yBry)3can range from any of the minimum values described above to any of the maximum values described above. For example, in CsxFA1-xPb(I1-yBry)3, x can be from greater than 0 to less than 1 (e.g., from greater than 0 to 0.5, from 0.5 to less than 1, from greater than 0 to 0.2, from 0.2 to 0.4, from 0.4 to 0.6, from 0.6 to 0.8, from 0.8 to less than 1, from greater than 0 to 0.8, from greater than 0 to 0.6, from greater than 0 to 0.4, from greater than 0 to 0.15, from 0.01 to less than 1, from 0.05 to less than 1, from 0.01 to 0.8, from 0.01 to 0.6, from 0.01 to 0.6, from 0.01 to 0.4, from 0.01 to 0.2, from 0.05 to 0.8, from 0.05 to 0.6, from 0.05 to 0.4, from 0.05 to 0.2, or from 0.05 to 0.15). In some examples, x is from 0.05 to 0.15. In some examples, x is 0.05, 0.07, 0.1, or 0.15. In some examples, x is 0.1.

[0201] In some examples of CsxFA1-xPb(I1-yBry)3, y is greater than 0 (e.g., 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.1 or more, 0.11 or more, 0.12 or more, 0.13 or more, 0.14 or more, 0.15 or more, 0.2 or more, 0.25 or more, 0.3 or more, 0.35 or more, 0.4 or more, 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more, 0.65 or more, 0.7 or more, 0.75 or more, 0.8 or more, 0.85 or more, 0.9 or more, or 0.95 or more). In some examples of CsxFAi JPb(li-yBry)3, y is 0.05 or more. In some10046-679W01: 8683 KOR examples of CsxFA1-xPb(I1-yBry)3, y is less than 1 (e.g., 0.95 or less, 0.9 or less, 0.85 or less, 0.8 or less, 0.75 or less, 0.7 or less, 0.65 or less, 0.6 or less, 0.55 or less, 0.5 or less, 0.45 or less, 0.4 or less, 0.35 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, 0.14 or less, 0.13 or less, 0.12 or less, 0.11 or less, 0.1 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, 0.04 or less, 0.03 or less, 0.02 or less, or 0.01 or less). In some examples of CsxFA1-xPb(I1-yBry)3, y is 0.15 or less. The value of y in CsxFA1-xPb(I1-yBry)3can range from any of the minimum values described above to any of the maximum values described above. For example, in CsxFA1-xPb(I1-yBry)3, y can be from greater than 0 to less than 1 (e.g., from greater than 0 to 0.5, from 0.5 to less than 1, from greater than 0 to 0.2, from 0.2 to 0.4, from 0.4 to 0.6, from 0.6 to 0.8, from 0.8 to less than 1, from greater than 0 to 0.8, from greater than 0 to 0.6, from greater than 0 to 0.4, from greater than 0 to 0.15, from 0.01 to less than 1, from 0.05 to less than 1, from 0.01 to 0.8, from 0.01 to 0.6, from 0.01 to 0.6, from 0.01 to 0.4, from 0.01 to 0.2, from 0.05 to 0.8, from 0.05 to 0.6, from 0.05 to 0.4, from 0.05 to 0.2, or from 0.05 to 0.15). In some examples, y is 0.05.

[0202] In some examples, x is from 0.05 to 0.15 and y is 0.05. In some examples, x is 0.05, 0.07, 0.1, or 0.15; and y is 0.05.

[0203] In some examples, the double cation perovskite comprises Cso.iFAo.9Pb(Io.95Bro.o5)3. In some examples, the double cation perovskite comprises Cso.iFAo.9Pb(Io.95Bro.o5)3 and is substantially free of methylammonium.

[0204] In some examples, the double cation perovskite consists essentially of Cso.iFAo.9Pb(Io.95Bro.os)3. In some examples, the double cation perovskite consists of

[0205] C so. iFAo.9Pb(Io.95Bro.o5)3.

[0206] Also disclosed herein are inks comprising any of the double cation perovskites disclosed herein and a solvent.

[0207] In some examples, the ink includes the perovskite at a concentration of 0.1 M or more (e.g., 0.2 M or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, 1.75 or more, 2 or more, 2.25 or more, 2.5 or more, or 2.75 or more). In some examples, the ink includes the perovskite at a concentration of 0.5 M or more. In some examples, the ink includes the perovskite at a concentration of 3 M or less (e.g., 2.75 M or less, 2.5 M or less, 2.25 M or less, 2 M or less, 1.75 M or less, 1.5 M or less, 1.4 M or less, 1.3 M or less, 1.2 M or less, 1.1 M or less, 1 M or less, 0.9 M or less, 0.8 M or less, 0.7 M or less, 0.6 M or less, 0.5 M or less, 0.4 M or less, 0.3 M or less, or 0.2 M or less). In some examples, the ink includes the perovskite at a concentration of 1.5 M or less. The concentration of the perovskite in the ink can range from any10046-679W01: 8683 KOR of the minimum values described above to any of the maximum values described above. For example, the concentration of the perovskite in the ink can be from 0.1 to 3 M (e.g., from 0.1 to 1.5 M, from 1.5 to 3 M, from 0.1 to 1 M, from 1 to 2 M, from 2 to 3 M, from 0.1 to 2.5 M, from 0.1 to 2 M, from 0.1 to 0.9 M, from 0.5 to 3 M, from 0.5 to 2 M, or from 0.5 to 1.5 M). In some examples, the concentration of the perovskite in the ink can be from 0.5 to 1.5 M, such as 0.9 M.

[0208] In some examples, the solvent comprises any of the solvent systems disclosed herein (e.g., comprising ACN and DMSO).

[0209] In some examples, the ink further comprises an additive.

[0210] In some examples, the additive comprises dodecylammonium iodide (DAI) (CH12H29IN). In some examples, the perovskite ink includes the additive at a concentration of greater than 0 mg / ml, (e.g., 0.1 mg / ml, or more, 0.5 mg / ml, or more, 1 mg / ml, or more, 1.5 mg / mL or more, 2 mg / ml, or more, 2.5 mg / mL or more, 3 mg / ml, or more, 3.5 mg / ml, or more, 4 mg / ml, or more, 4.5 mg / mL or more, 5 mg / mL or more, 5.5 mg / mL or more, 6 mg / mL or more, 6.5 mg / ml, or more, 7 mg / ml, or more, 7.5 mg / ml, or more, 8 mg / ml, or more, 8.5 mg / ml, or more, 9 mg / ml, or more, or 9.5 mg / ml, or more). In some examples, the perovskite ink includes the additive at a concentration of 0.1 mg / mL or more. In some examples, the perovskite ink includes the additive at a concentration of 1 mg / mL or more. In some examples, the perovskite ink includes the additive at a concentration of 10 mg / ml, or less (e.g., 9.5 mg / ml, or less, 9 mg / ml, or less, 8.5 mg / ml, or less, 8 mg / ml, or less, 7.5 mg / ml, or less, 7 mg / ml, or less, 6.5 mg / ml, or less, 6 mg / mL or less, 5.5 mg / mL or less, 5 mg / mL or less, 4.5 mg / mL or less, 4 mg / mL or less, 3.5 mg / ml, or less, 3 mg / ml, or less, 2.5 mg / ml, or less, 2 mg / ml, or less, 1.5 mg / ml, or less, 1 mg / ml, or less, or 0.5 mg / ml, or less). In some examples, the perovskite ink includes the additive at a concentration of 5 mg / mL or less. In some examples, the perovskite ink includes the additive at a concentration of 3 mg / ml, or less. The concentration of the additive in the perovskite ink can range from any of the minimum values described above to any of the maximum values described above. For example, the perovskite ink can include the additive at a concentration of from greater than 0 to 10 mg / mL (e.g., from greater than 0 to 5 mg / mL, from 5 to 10 mg / mL, from greater than 0 to 2 mg / ml,, from 2 to 4 mg / ml,, from 4 to 6 mg / mL,, from 6 to 8 mg / ml,, from 8 to 10 mg / mL, from greater than 0 to 8 mg / mL, from greater than 0 to 6 mg / mL, from greater than 0 to 4 mg / mL, from 0.1 to 10 mg / mL, from 0.1 to 8 mg / mL, from 0.1 to 6 mg / mL, from 0.1 to 4 mg / ml,, from 0.1 to 2 mg / mL,, from 1 to 10 mg / mL,, from 1 to 8 mg / ml,, from 1 to 6 mg / mL,, from 1 to 4 mg / ml,, or from 1 to 3 mg / ml,). In some examples, the perovskite ink includes the additive at a concentration of from 0.1 to 10 mg / mL. In some examples, the perovskite ink includes the additive at a concentration of from 1 to 10 mg / mL,. In some examples, the10046-679W01: 8683 KOR perovskite ink includes the additive at a concentration of from 1 to 5 mg / mL. In some examples, the perovskite ink includes the additive at a concentration of from 1 to 3 mg / mL, such as 2 mg / mL.

[0211] In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film.

[0212] In some examples, the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink.

[0213] In some examples, the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture.

[0214] In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of greater than 0 mg / mL (e.g., 0.1 mg / mL or more, 0.5 mg / mL or more, 1 mg / mL or more, 1.5 mg / mL or more, 2 mg / mL or more, 2.5 mg / ml, or more, 3 mg / mL or more, 3.5 mg / mL or more, 4 mg / mL or more, 4.5 mg / mL or more, 5 mg / ml, or more, 5.5 mg / ml, or more, 6 mg / ml, or more, 6.5 mg / mL or more, 7 mg / ml, or more, 7.5 mg / mL or more, 8 mg / mL or more, 8.5 mg / mL or more, 9 mg / mL or more, or 9.5 mg / mL or more). In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of 0.1 mg / mL or more. In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of 1 mg / mL or more. In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of 10 mg / ml, or less (e.g., 9.5 mg / ml, or less, 9 mg / ml, or less, 8.5 mg / ml, or less, 8 mg / mL or less, 7.5 mg / mL or less, 7 mg / mL or less, 6.5 mg / mL or less, 6 mg / mL or less, 5.5 mg / ml, or less, 5 mg / ml, or less, 4.5 mg / ml, or less, 4 mg / ml, or less, 3.5 mg / ml, or less, 3 mg / ml, or less, 2.5 mg / ml, or less, 2 mg / ml, or less, 1.5 mg / ml, or less, 1 mg / ml, or less, or 0.5 mg / mL or less). In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of 5 mg / mL or less. In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of 3 mg / mL or less. The additive comprises dodecylammonium iodide (DAI) and the concentration of the additive in the perovskite ink can range from any of the minimum values described above to any of the maximum values described above. For example, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink can include the additive at a concentration of from greater than 0 to 10 mg / mL (e.g., from greater than 0 to 5 mg / mL, from 5 to 10 mg / mL, from greater than 0 to 2 mg / mL, from 2 to 4 mg / mL,10046-679W01: 8683 KOR from 4 to 6 mg / mL, from 6 to 8 mg / mL, from 8 to 10 mg / mL, from greater than 0 to 8 mg / mL, from greater than 0 to 6 mg / mL, from greater than 0 to 4 mg / mL, from 0.1 to 10 mg / mL, from 0.1 to 8 mg / mL, from 0.1 to 6 mg / mL, from 0.1 to 4 mg / mL, from 0.1 to 2 mg / mL, from 1 to 10 mg / mL, from 1 to 8 mg / mL, from 1 to 6 mg / mL, from 1 to 4 mg / mL, or from 1 to 3 mg / mL). In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of from 0.1 to 10 mg / mL. In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of from 1 to 10 mg / mL. In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of from 1 to 5 mg / mL. In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of from 1 to 3 mg / mL, such as 2 mg / mL.

[0215] In some examples, the additive comprises dodecylammonium iodide (DAI) and the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film.

[0216] In some examples, the additive comprises dodecylammonium iodide (DAI) and the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink.

[0217] In some examples, the additive comprises dodecylammonium iodide (DAI) and the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture.

[0218] In some examples, the ink can further comprise MAO, for example in an amount of 10 mol%.

[0219] Inks comprising an additive

[0220] Also disclosed herein are perovskite inks comprising a perovskite, a solvent, and an additive, wherein the additive comprises dodecylammonium iodide (DAI).

[0221] In some examples, the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0222] In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL. In some examples, the additive comprises dodecylammonium iodide (DAI) and the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0223] In some examples, the additive can improve grain size and / or crystallinity of a perovskite10046-679W01: 8683 KOR film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film. In some examples, the additive comprises dodecylammonium iodide (DAI) and the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film.

[0224] In some examples, the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink. In some examples, the additive comprises dodecylammonium iodide (DAI) and the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink.

[0225] In some examples, the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture. In some examples, the additive comprises dodecylammonium iodide (DAI) and the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture.

[0226] In some examples, the perovskite comprises a double cation perovskite. In some examples, the cations comprise FA and Cs.

[0227] In some examples, the perovskite is substantially free of methylammonium.

[0228] In some examples, the perovskite is a multi-halide perovskite. In some examples, the halides comprise I and Br.

[0229] In some examples, the perovskite is any of the perovskites disclosed herein (e.g., any of the double cation perovskites disclosed herein).

[0230] In some examples, the solvent comprises any of the solvent systems disclosed herein (e.g., comprising ACN and DMSO).

[0231] Solvent Systems and Inks based thereon

[0232] Also disclosed herein are solvent systems for preparing perovskite films from perovskite inks, the solvent system comprising acetonitrile (ACN) and dimethyl sulfoxide (DMSO).

[0233] In some examples, the DMSO is a coordinating solvent to dissolve the perovskite and acetonitrile is a diluting solvent.

[0234] In some examples, the solvent system is substantially free of methylamine.

[0235] In some examples, the solvent system comprises ACN in an amount of greater than 0% (v / v), based on the total volume of ACN and DMSO (e.g., 1% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55%’ or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, or 95% or more). In some examples, the solvent10046-679W01: 8683 KOR system comprises ACN in an amount of 1% (v / v) or more, based on the total volume of ACN and DMSO. In some examples, the solvent system comprises ACN in an amount of 10% (v / v) or more, based on the total volume of ACN and DMSO. In some examples, the solvent system comprises ACN in an amount of 50% (v / v) or more, based on the total volume of ACN and DMSO. In some examples, the solvent system comprises ACN in an amount of less than 100% (v / v), based on the total volume of ACN and DMSO (e.g., 99% or less, 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less). In some examples, the solvent system comprises ACN in an amount of 99% (v / v) or less, based on the total volume of ACN and DMSO. In some examples, the solvent system comprises ACN in an amount of 90% (v / v) or less, based on the total volume of ACN and DMSO. In some examples, the solvent system comprises ACN in an amount of 83.3% (v / v) or less, based on the total volume of ACN and DMSO. In some examples, the solvent system comprises ACN in an amount of 75% (v / v) or less. The amount of ACN in the solvent system can range from any of the minimum values described above to any of the maximum values described above. For example, the solvent system can comprise ACN in an amount of from greater than 0 to less than 100 % (v / v) based on the total volume of ACN and DMSO (e.g., from greater than 0 to 50%, from 50 to less than 100%, from greater than 0 to 20%, from 20 to 40%, from 40 to 60%, from 60 to 80%, from 80 to less than 100%, from greater than 0 to 80%, from greater than 0 to 60%, from greater than 0 to 40%, from 1 to less than 100%, from 10 to less than 100%, from 20 to less than 100%, from 40 to less than 100%, from 60 to less than 100%, from 1 to 99%, from 10 to 95%, from 20 to 95%, from 40 to 95%, from 50 to 90%, from 50 to 83.3%’, or from 50 to 75%). In some examples, the solvent system comprises ACN in an amount of from 50 to 83.3% (v / v), based on the total volume of ACN and DMSO. In some examples, the solvent system comprises ACN in an amount of from 50 to 75% (v / v), such as 66% (v / v), based on the total volume of ACN and DMSO.

[0236] In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN:DMSO) of 10:1 or less (e.g., 9:1 or less, 8:1 or less, 7:1 or less, 6:1 or less, 5:1 or less, 4:1 or less, 3:1 or less, 2:1 or less, 1:1 or less, 1:2 or less, 1:3 or less, 1:4 or less, 1:5 or less, 1:6 or less, 1:7 or less, 1:8 or less, or 1:9 or less). In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN:DMSO) of 5:1 or less. In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN:DMSO) of 3:1 or less. In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN:DMSO) of 1:10 or more (e.g., 1:9 or more, 1:8 or more, 1:7 or more, 1:6 or more, 1:5 or more, 1:4 or more,10046-679W01: 8683 KOR 1:3 or more, 1:2 or more, 1:1 or more, 2:1 or more, 3:1 or more, 4:1 or more, 5:1 or more, 6:1 or more, 7:1 or more, 8:1 or more, or 9:1 or more). In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN: DMSO) of 1:1 or more. The volume ratio of ACN and DMSO (ACN: DMSO) in the solvent system can range from any of the minimum values described above to any of the maximum values described above. For example, the solvent system can comprise ACN and DMSO in a volume ratio (ACN:DMSO) of from 10:1 to 1:10 (e.g., from 10:1 to 1:1, from 1:1 to 1:10, from 10:1 to 5:1, from 5:1 to 1:1, from 1:1 to 1:5, from 1:5 to 1:10, from 10:1 to 1:5, from 5:1 to 1:10, from 9:1 to 1:9, from 5:1 to 1:5, or from 3:1 to 1:1). In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN:DMSO) of from 5:1 to 1:1. In some examples, the solvent system comprises ACN and DMSO in a volume ratio (ACN:DMSO) of from 3:1 to 1:1, such as 2:1.

[0237] In some examples, the solvent system consists essentially of acetonitrile and dimethyl sulfoxide (DMSO). In some examples, the solvent system consists of acetonitrile and dimethyl sulfoxide (DMSO).

[0238] Also disclosed herein are inks (e.g., perovskite inks) comprising a perovskite and any of the solvent systems disclosed herein (e.g., comprising ACN and DMSO).

[0239] In some examples, the perovskite comprises a double cation perovskite. In some examples, the cations comprise FA and Cs.

[0240] In some examples, the perovskite is substantially free of methylammonium.

[0241] In some examples, the perovskite is a multi-halide perovskite. In some examples, the halides comprise I and Br.

[0242] In some examples, the perovskite is any of the perovskites disclosed herein (e.g., any of the double cation perovskites disclosed herein).

[0243] In some examples, the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0244] In some examples, the ink further comprises an additive. In some examples, the additive comprises dodecylammonium iodide (DAI). In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL. In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film. In some examples, the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink. In some examples, the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture.10046-679W01: 8683 KOR In some examples, the ink is ambient processable.

[0245] In some examples, the ink is less toxic than a similar ink comprising conventional perovskite ink processing solvents.

[0246] In some examples, the ink is greener than a similar ink comprising conventional perovskite ink processing solvents.

[0247] In some examples, the ink is compatible with blade coating, such as air knife-assisted ambient blade coating.

[0248] In some examples, the ink is compatible with roll-to-roll processing.

[0249] In some examples, the ink is compatible with flexible substrates.

[0250] In some examples, the ink is compatible with flexible microgroove substrates, such as those described in Blackburn et al. ACS Applied Energy Materials, 2025, 8(4), 2219-2228; Pernik et al. 2016, ACS Energy Letters, 1(5), 1021-1027; Wong-Stringer et al. 2019, Energy and Environmental Science, 2019, 12(6), 1928–1937; WO 2014 / 118545 and / or WO 2012 / 175902, each of which is hereby incorporated herein by reference for its description thereof.

[0251] In some examples, the ink is capable of preparing a perovskite film on a substrate, such as the flexible microgroove substrate, that is substantially more uniform relative to a film prepared using conventional perovskite ink processing solvents.

[0252] Methods of Makin g Perovskite Films

[0253] Also disclosed herein are methods of making perovskite films, the methods comprising depositing a perovskite ink on a substrate, wherein the perovskite ink comprises a perovskite and a solvent, wherein the perovskite is any of the perovskites disclosed herein, the solvent is any of the solvent systems disclosed herein, the perovskite ink is any of those disclosed herein, or a combination thereof.

[0254] In some examples, the perovskite is any of the perovskites disclosed herein (e.g., any of the double cation perovskites disclosed herein).

[0255] In some examples, the solvent is any of the solvent systems disclosed herein (e.g., comprising ACN and DMSO).

[0256] In some examples, the perovskite is any of the perovskites disclosed herein (e.g., any of the double cation perovskites disclosed herein) and the solvent is any of the solvent systems disclosed herein (e.g., comprising ACN and DMSO).

[0257] In some examples, the perovskite ink is any of the inks disclosed herein.

[0258] In some examples, the perovskite ink further comprises an additive. In some examples, the additive comprises dodecylammonium iodide (DAI). In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL. In10046-679W01: 8683 KOR some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film. In some examples, the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink. In some examples, the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture.

[0259] In some examples, the method further comprises pre-treating the substrate before depositing the perovskite ink.

[0260] In some examples, pre-treating comprises depositing a pre-treatment compound onto the substrate before depositing the perovskite ink.

[0261] In some examples, the pre-treatment compound modifies the surface energy of the substrate, for example by optimizing the surface Fermi level, passivating at least a portion of the surface to reduce defect density, improving wettability, or a combination thereof.

[0262] In some examples, the pre-treatment compound comprises phenethylammonium iodide (PEAI) (C₈H₁₂IN).

[0263] Also disclosed herein are methods of making a perovskite film, comprising pre-treating a substrate with a pretreatment compound comprising phenethylammonium iodide (PEAI), and subsequently depositing a perovskite ink on the pre-treated substrate, wherein the perovskite ink comprises a perovskite and a solvent. In some examples, pre-treating comprises depositing the pre-treatment compound onto the substrate before depositing the perovskite ink. In some examples, the pre-treatment compound modifies the surface energy of the substrate, for example by optimizing the surface Fermi level, passivating at least a portion of the surface to reduce defect density, improving wettability, or a combination thereof.

[0264] In some examples, the perovskite comprises a double cation perovskite. In some examples, the cations comprise FA and Cs.

[0265] In some examples, the perovskite is substantially free of methylammonium.

[0266] In some examples, the perovskite is a multi-halide perovskite. In some examples, the halides comprise I and Br.

[0267] In some examples, the perovskite is any of the perovskites disclosed herein (e.g., any of the double cation perovskites disclosed herein).

[0268] In some examples, the solvent is any of the solvent systems disclosed herein (e.g., comprising ACN and DMSO).

[0269] In some examples, the perovskite is any of the perovskites disclosed herein (e.g., any of the double cation perovskites disclosed herein) and the solvent is any of the solvent systems10046-679W01: 8683 KOR disclosed herein (e.g., comprising ACN and DMSO).

[0270] In some examples, the perovskite ink is any of the inks disclosed herein.

[0271] In some examples, the perovskite ink further comprises an additive. In some examples, the additive comprises dodecylammonium iodide (DAI). In some examples, the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL. In some examples, the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film. In some examples, the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink. In some examples, the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture.

[0272] The substrate can comprise any substrate consistent with the methods disclosed herein. In some examples, the substrate is rigid.

[0273] In some examples, the substrate comprises glass.

[0274] In some examples, the substrate comprises silicon.

[0275] In some examples, the substrate is flexible.

[0276] In some examples, the substrate is flexible and comprises a polymer, such as an acrylic polymer, polyethylene terephthalate, or a combination thereof.

[0277] In some examples, the substrate is substantially flat.

[0278] In some examples, the substrate is grooved, such as with microgrooves. In some examples, the substrate is a flexible microgroove substrate, such as those described in Blackburn et al. ACS Applied Energy Materials, 2025, 8(4), 2219-2228; Pernik et al. 2016, ACS Energy Letters, 1(5), 1021-1027; Wong-Stringer et al. 2019, Energy and Environmental Science, 2019, 12(6), 1928–1937; WO 2014 / 118545 and / or WO 2012 / 175902, each of which is hereby incorporated herein by reference for its description thereof.

[0279] Depositing can comprise any deposition technique consistent with the methods disclosed herein, such as those known in the art. In some examples, depositing comprises spin coating, blade coating, slot-die coating, gravure coating, chemical bath / vapor deposition, roll-to-roll processing, spray coating, or a combination thereof. In some examples, depositing comprises blade coating, slot-die coating, gravure coating, chemical bath / vapor deposition, roll-to-roll processing, or a combination thereof. In some examples, depositing comprises blade coating, such as air knife-assisted ambient blade coating. In some examples, depositing comprises roll-to-roll processing.

[0280] In some examples, the method is performed at ambient conditions.10046-679W01: 8683 KOR Perovskite Films and Methods of Use thereof

[0281] Also disclosed herein are perovskite films made by any of the methods disclosed herein. In some examples, the film comprises the perovskite as a-phase.

[0282] Also disclosed herein are methods of use of any of the perovskite films made by any of the methods disclosed herein. In some examples, the method comprises using the film in a photovoltaic device, such as a solar cell. In some examples, the method comprises using the film for sensing, for catalysis, in a battery, in a LED, or a combination thereof.

[0283] Also disclosed herein are articles of manufacture comprising any of the perovskite films made by any of the methods disclosed herein. In some examples, the article is a photovoltaic device, such as a solar cell. In some examples, the article is a battery, LED, or a combination thereof.

[0284] Also disclosed herein are photovoltaic devices comprising any of the perovskite films made by any of the methods disclosed herein. In some examples, the photovoltaic device is a solar cell. In some examples, the device is an ambient-processable acetonitrile / dimethyl sulfoxide-based microgroove perovskite photovoltaic device.

[0285] EXAMPLES

[0286] The following examples are set forth below to illustrate the methods and results according to the disclosed subject matter. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative methods and results. These examples are not intended to exclude equivalents and variations of the present invention which are apparent to one skilled in the art.

[0287] Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. There are numerous variations and combinations of measurement conditions, e.g., component concentrations, temperatures, pressures and other measurement ranges and conditions that can be used to optimize the described process.

[0288] Example 1

[0289] Disclosed herein are compositions, systems, and methods for ambient-processable acetonitrile / dimethyl sulfoxide-based microgroove perovskite photovoltaic devices.

[0290] Material: acetonitrile / DMSO perovskite solution processed microgroove photovoltaic devices.

[0291] Process: Using acetonitrile / DMSO solutions to blade coat microgroove photovoltaic substrates.10046-679W01: 8683 KOR Method: acetonitrile / DMSO is a greener and less toxic alternative to traditional methods. Dimethyl sulfoxide is used as a coordinating solvent to dissolve lead halide perovskite precursors; which comprise lead (II) iodide, lead bromide, formamidinium iodide, cesium iodide, and methylammonium chloride, in acetonitrile to develop a new ink formulation compatible with blade coating. Photovoltaic devices are made via air knife-assisted ambient blade coating of the Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite ink into microgroove photovoltaic substrates, which comprise micron-scale grooves of an interdigitated back contact flexible substrate with n- and p-type transport layers thermally deposited on opposite groove walls. 'The compositions and methods disclosed herein allow for the use of less toxic solvent alternatives to conventional perovskite ink processing solvents. This less toxic solvent system also allows for ambient deposition and therefore improves the ability for scale-up into high throughput and low-cost roll-to-roll processing.

[0292] The use of DMSO as a coordinating solvent, which is then diluted by acetonitrile is new in design and application. Current perovskite ink coating technologies do not utilize such a combination of solvents to produce perovskite films.

[0293] Solvent toxicity is improved upon, since much more toxic solvents are traditionally used with acetonitrile -based inks, such as methylamine, which pose a significant risk to health and environment.

[0294] Additionally, the properties of this solvent system allow for refined control over perovskite film quality while maintaining high throughput production speeds.

[0295] The microgroove based photovoltaic (PV) architecture is produced roll-to-roll on lightweight flexible substrates that offer significant advantages in cost / watt and power / weight metrics as compared to traditional rigid silicon and tandem technologies.

[0296] Shelf-life of the mixed ink can be investigated and potentially improved by identifying proper storage conditions and / or procedures.

[0297] Perovskite films are widely used in various other applications, such as sensing, catalysis, batteries, LEDs, etc. Therefore, this technology can provide opportunities for improved processing of perovskites in these technologies as well.

[0298] Example 2

[0299] The performance of metal halide perovskite photovoltaic devices has significantly improved in a relatively short timeframe, with power conversion efficiencies rising dramatically from 3.8% in 2009 to the current records of 25.7% for single junction and 32.5% for perovskite / silicon tandem cells. There is continued optimism that perovskite solar cells (PSCs) will become commercially and widely available in the near future, offering solar cell materials that are10046-679W01: 8683 KOR suitable for low-cost and high -efficiency tandem cells, flexible devices, and low-temperature, high-throughput manufacturing.

[0300] Significant strides have been made in the development of flexible PSCs over the last decade. Flexible substrates such as acrylic or polyethylene terephthalate are ideal candidates for meeting the demand for lightweight, easy to install, and cost-effective solar devices. However, the processing involved in adequately fabricating PSCs on these flexible substrates often faces challenges such as uniformity, pinhole formation, and mechanical robustness. Microgroove substrates are an innovative approach to achieving flexible device performance on a roll-to-roll scale by improving structural stability while maintaining adequate performance. Nonetheless, coating perovskite films onto topographically complex surfaces such as this presents challenges related to uniform deposition and film quality.

[0301] One area of concern that should be addressed before the commercialization of PSCs is the uniformity and quality of large-scale deposition of perovskite materials, especially onto topographically complex surfaces. Traditional small-scale coating methods in the PSC field such as spin coating face limitations such as scalability, material waste, and suboptimal film uniformity. Blade coating allows for the deposition of thicker films with more control over morphology and can act as a stepping-stone between lab-scale research and large-scale commercial production. The similarities between blade coating and conventional large-area deposition techniques such as slot-die coating, gravure coating, or chemical bath / vapor deposition allows for relatively easy adaptations to fit the need of various process spaces.

[0302] The solvent system presented here is designed to address the issues associated with large-area deposition of perovskite films by engineering solvent properties to improve the coating behavior, film formation, and overall performance of the flexible PSCs on microgroove substrates. By using a new mixture of solvents, an aim is to optimize the blade coating process to show the potential for scalable high-performance PSC production. This discovery may pave the way for future innovations toward safer large-scale commercial production of efficient, cost- effective, and durable flexible PSCs.

[0303] Described herein is a method for fabricating perovskite photovoltaic (PV) devices using an ambient-processable solution composed of FA / Cs Cations with acetonitrile (ACN) and dimethyl sulfoxide (DMSO) solvent systems. The process leverages a microgroove-structured substrate, which enhances light absorption and charge transport, potentially improving overall solar cell efficiency.

[0304] Features:

[0305] • Solvent System (ACN / DMSO): Enables low-temperature processing of perovskite10046-679W01: 8683 KOR films, making the fabrication more scalable and cost-effective than high-temperature or vacuum-based methods.

[0306] • FA / Cs based inks provide improved longevity - FA / Cs cation based perovskite inks have shown exceptional longevity capability. Combined with this new ambient and green solvent system will allow for simplified production and higher performance.

[0307] • Microgroove Architecture: The structured substrate promotes improved light trapping and charge carrier dynamics, leading to higher performance and stability in the PV device.

[0308] • Ambient Compatibility: Unlike traditional perovskite processing that often requires inert environments, this approach allows manufacturing under ambient conditions, simplifying production and reducing costs.

[0309] • Scalability for Roll-to-Roll Production: The method is suited for large-area, flexible, and lightweight perovskite solar panels, which could be used in applications like building- integrated photovoltaics (BIPV) or portable energy solutions.

[0310] Potential Advantages:

[0311] • Reduced manufacturing complexity compared to conventional perovskite solar cell fabrication.

[0312] • Enhanced durability and efficiency due to the micro structured surface.

[0313] • Compatibility with flexible substrates for next-generation solar energy applications. Benefits:

[0314] • Flexible lightweight microgroove based solar PV can achieve a 20X power to weight ration advantage over traditional Silicon based PV panels.

[0315] • Utilization of 'green' environmentally friendly solvent systems for printing the perovskite ink will allow for standardized R2R production techniques in an ambient environment, drastically reducing capital equipment cost,

[0316] The systems here have been tested in some examples in lab / benchtop systems producing 100 cm2panels.

[0317] Example 3 - Perovskites Microgroove Photovoltaics for Cost-Effective Roll-to-Roll Production of Flexible Solar Cells

[0318] Microgroove photovoltaic substrates, which are made up of micron-scale grooves forming interdigitated back contact cells produced by thermally depositing n- and p-type transport layers on opposite groove walls, allow for photovoltaic arrays with tunable voltages compatible with roll-to-roll processing. A perovskite layer is deposited and used as the active material. The deposition and surface interactions of the perovskite are key to the device performance and longevity. This work explores transport layer pre- treatments, perovskite10046-679W01: 8683 KOR photovoltaic active layer compositions, and perovskite post-treatments used to improve photovoltaic performance while maintaining the advantage of scalable roll-to-roll production. It is shown that PEAI pre-treatment to the transport layers resulted in an enhanced photovoltaic performance (Figure 1). Additionally, different compositions of lead halide perovskites were explored. Results show that the performance of devices are highly dependent on the A-site cation compositions. It was found that the double cation perovskite, CsFAPb(I / Br)3, exhibited the highest photovoltaic performance. 'Through the application of the scalable deposition technique of blade coating, the use of PEAI pretreatment, and a double cation perovskite composition the photovoltaic performance was increased by a factor of 5 (Figure 1). In addition to improving the performance, methods to increase the longevity were explored. A post treatment of L-alpha- phosphatidylcholine before encapsulation with a 3M barrier film was found to increase the longevity of the photovoltaic devices, retaining 51% of their original efficiency after 8 months compared to 12% for devices encapsulated with barrier film alone, and 10% for unencapsulated devices.

[0319] Example 4 - Perovskites Microgroove Photovoltaics for Cost-Effective Roll-to-Roll Production of Flexible Solar Cells

[0320] Let’s Get Groovy. Perovskites are a breakthrough material in photovoltaic research because of their outstanding capability to capture sunlight and achieve high Power Conversion Efficiency (PCE). Their inexpensive, solution-processable manufacturing methods make them a promising alternative to conventional silicon-based solar cells. Microgroove photovoltaic substrates allow for photovoltaic arrays with tunable voltages compatible with roll-to-roll processing on flexible substrates (Figure 2).

[0321] Towards Scalability (Figure 3). Issues limiting commercialization of perovskites: non-scalable ink deposition techniques; deposition-dependent performance; lack of long-term material stability’. Issues specific to microgrooves: groove fill; energy mismatch between active and transport layers.

[0322] Results and Discussion

[0323] Pretreatments to transport layers. Blade coating phenethylammonium iodide (PEAI) as pretreatment increased the PCE by a factor of 5 (Figure 4). Pretreatment also improves groove fill (Figure 5) and aligns mismatches in energy levels (CB of PVK and LUMO of C60).

[0324] Active layer material and deposition optimization. Different active material affects surface morphology: MAPI - numerous pinholes (10.44%) and cracks; CsFAPbl / Br - more uniform and lower void density (2.28%); CsFAMAPbl / Br - few voids (2.66%) (Figure 6). Blade coating improves groove fill and leads to higher PCE (Figure 7 and Figure 8).10046-679W01: 8683 KOR Encapsulation. Devices treated with L-alpha-phosphatidylcholine (LaP) before encapsulation with 3M barrier film saw improved stability. LaP devices retained 51% PCE after 8 months (Figure 9); Barrier film alone retained 12% PCE (Figure 10).

[0325] Conclusion. PEAI pre -treatment enhanced the PCT 5x. CsFAPbIZBr exhibited the highest photovoltaic PCE. LaP post-treatment improved stability compared to barrier film alone.

[0326] Example 5 - Plastic Solar Cells with Back Contact Microgroove Architecture and Multi-Cation Perovskite Absorber

[0327] ABSTRACT. Perovskite photovoltaic devices (PVs) were fabricated on plastic substrates of polyethylene terephthalate (PET) embossed with micrometer- scale grooves (Figure 11). The electron and hole transport layers are deposited on the walls of the microgrooves, which are then filled with metal halide perovskite as the light-absorber. These microgroove solar cells are electrically connected in series to generate a high open circuit voltage (Voc>300 V). A range of perovskite formulations were examined and it was found that cesium formamidinium lead halide (Cso.1FAo.9PbI2.s5Bro.15) provides significantly improved performance compared to both methylammonium lead iodide ((CIUNILlPbE, MAPI) or Cs / FA / MA triple cation perovskites. The small concentrations of bromide (I0.95Br0.05) stabilize the perovskite phase. The double cation perovskite deposits more uniformly on the patterned PET substrates, with fewer pinholes and voids, and exhibits significantly longer photoluminescence (PL) lifetimes, indicative of fewer defects. Device performance was further improved by treating substrates with phenethylammonium iodide (PEAI) prior to perovskite deposition.

[0328] Introduction. Metal halide perovskite PVs have significantly advanced over the past decade, with record power conversion efficiencies (PCEs) for single junction devices increasing from 3.8%’ to over 26% [Al, A2], Perovskites exhibit high absorption coefficients [A3], tunable bandgaps [A4], long charge carrier lifetimes [A5], and low exciton binding energies [ A6].

[0329] Understanding and optimizing perovskite morphology; namely the composition [A7], crystallization [A8], and interfaces of the perovskite film [A9] can lead to more efficient and reliable perovskite solar cells (PSCs) [AlOj.

[0330] All-back-contact solar cells represent an alternative to traditional planar architecture devices. In this design, the absorber layer is not buried under a window layer and is fully exposed to the light source [All, A 12]. A flexible back-contact architecture based on a V-shaped microgroove structure was reported in 2019 where the individual grooves act as photovoltaic devices and are patterned in an acrylate film on a polyethylene terephthalate (PET) substrate [A12]. Pernik et al. used this architecture to fabricate devices made with CuInSe2 nanocrystal absorber films [A 13]. Although they had low efficiencies (4.4% PCE), their approach to PV10046-679W01: 8683 KOR device fabrication is highly versatile and could be applied to any solution-processable perovskite materials [A 13]. Wong-Stringer et al. demonstrated the viability of this technology where they fabricated flexible Methylammonium lead halide (MAPbI3) microgroove back-contact solar cells achieving a PCE of 7.3% [A12]. Blackburn et al. explored scaling up of this technology via slot-die coating of MAPbI3back-contact solar cells and achieved a stabilized efficiency of 12.8% [A14].

[0331] Perovskite film formulations with methylammonium (MA+) are susceptible to thermal degradation [A 15], compromising their long-term stability. This is due to the volatility of MA+molecules which degrade at high temperatures (~80°C) [A15] close to the solar cell operating conditions. As a result, there is a growing necessity in developing MA-free perovskites systems to achieve both high efficiency and enhanced long-term stability [A16-A19]. Purely inorganic perovskites such as cesium (Cs) based perovskite, CsPbb, with a bandgap of 1.73eV, are only stable at high temperatures and convert to an undesired yellow (8) phase at room temperature [A20, A21], In recent years, a formamidinium (FA) based perovskite, FAPbh, has aroused great interest for its enhanced thermal stability and more optimal band gap for solar applications [A22], However, FA+is a relatively large cation that induces distortion to the 3D perovskite lattice from the photoactive black phase, resulting in a photoinactive yellow (3) phase at room temperature [A23], To suppress this distortion, multi-cation and / or multihalide compositions have been explored [A24-A26]. It has been proven that the addition of small amounts of Cs, forming a triple cation (Cs / FA / MA) perovskite, facilitates the growth of the a-phase structure at room temperature and enhances the thermal stability and performance of the devices [A23, A27], Moreover, the addition of small amounts of bromine Br, forming a multi-halide (I / Br) perovskite, is crucial for obtaining high-quality films and enhanced phase stability as bromine incorporation affects the phase transformation and crystallization kinetics of the perovskite films [ A26].

[0332] The morphology of perovskite films is affected by composition and it is one of the most important factors that influence the efficiency of the prepared material [A28, A29], A smooth surface, absent of pinholes with large crystal grain size helps improve performance and stability [ A30]. Saliba et al reported that adding Cs to MA / FA mixtures induces large uniform perovskite grains and high quality perovskite films which are resistant to subtle variations during the fabrication process enabling better reproducibility [A27J. Moreover, Srathongsian et al. showed that the concentration of Cs and Br in (CsFAMA)Pb(IZBr) systems affects film morphology [A31]. High Cs+content results in wrinkled morphology which leads to a poor interface between the pero vskite and the hole transport layer; compared to an optimal Cs and Br content which leads to no wrinkles in the film and higher device efficiency [ A31]. It was found herein that10046-679W01: 8683 KOR double-cation CsFA films are much more uniform, with fewer pinholes and voids as well as significantly longer PL lifetimes. The double cation devices significantly outperformed the MAPI and triple cation devices. Moreover, pre-treating with phenethylammonium iodide (PEAI) contributed to uniform coating along the length of the grooves, increased the groove fill, and enhanced the photovoltaic performance of the fabricated devices.

[0333] Results and Discussion. Different perovskite compositions of MAPbL, double cation Cso.iFAo.9Pb(Io.95Bro.o5)3, (CsFA), and triple cation Cso.o5FAo.79MAo.i6Pb(Io.85Bro.i5)3, (CsFAMA), were deposited on all back contact plastic solar cells with perovskite absorber material integrated into a microgroove cascade design, as shown in Figure 12. The solar cells are fabricated on PET substrates patterned with an array of aligned microgrooves, evident via the colorful optical interference of the reflected light (Figure 12a). These back-contact devices are composed of electron and hole transport layers on opposing sides of the groove with the perovskite material deposited in between transport layers [A 14]. Electron transport layer (ETL) is composed of a Ti / SnO2 / C60 multilayer, and the hole transport layer (HTL) is composed of Ni / NiO as depicted in Figure 12c.

[0334] CsxFAi-xPb(Ii-yBry)3 layers were deposited with different amounts of Cs+and FA+: x=0, 0.05, 0.07, 0.10 and 0.15. Br was also added to some films to improve perovskite phase stability: y=0 or 0.05. As shown from the XRD patterns in Figure 13, the perovskite structure is greatly affected by the Cs ratio. The films without Cs (i.e., FAPbb where x=0) have a dominant peak at 11.8°, which corresponds to the hexagonal non-perovskite yellow phase of FAPbb (i.e., S-FAPbL). Films with 5% Cs (x=0.05) have 3 characteristic peaks at 11.8°, 12.7°, and 14.0°, which correspond to the hexagonal FAPbb phase, lead iodide, and alpha FAPbb perovskite phase, respectively. For x=0.10, a pure alpha perovskite phase was obtained; however, when x>0.10, the yellow phase appears again. This is not the case when bromide is added (Figure 13b) where even small concentrations of bromide (y=0.05) stabilize the perovskite phase. All the films with varying Cs content (x=0.05, 0.07, 0.10 and 0.15) have a dominant a-FAPbL phase. Therefore, Cs0.1FA0.9Pb(I0.95Br0.05)3 is chosen as the optimized composition for double cation perovskites herein.

[0335] Figure 14 shows the photovoltaic parameters of 30 devices fabricated with three different perovskite compositions: (1) MAPbL since it’s the most commonly used perovskite material, (2) Cso.iFAo.9Pb(Io.95Bro.o5)3 after optimization of its cation and anion ratios (see Figure 13), and (3) Cs0.05FA0.79MA0.16Pb(I0.85Br0.15)3 as these ratios are proved to give highly uniform robust perovskite films [A27, A32], There is a significant variation in performance with the use of different perovskite compositions. The average values of power conversion efficiency (PCE),10046-679W01: 8683 KOR open circuit voltage (Voc), and short circuit current density (Jsc) are 0.88 %, 127 V, and 12.8 mA / cm2, respectively, were highest for Cso.iFAo.9Pb(Io.95Bro.o5)3. It is noted that this double cation material was used as a photo absorber for thin film flat cells as depicted in Figure 30. Results show that this material performs well in a flat cell, 8 devices were fabricated and the average PCE, Voc, and Jsc were 12.6 %, 0.84 V, and 29.5 mA / cm2, respectively.

[0336] Figure 15 shows absorptance spectra of perovskite layers thin films with different compositions. The optical band gap (Eg) of each film was determined from Tauc plots of the absorbance spectra (Figure 21) [A33J. The absorption onset of MAPI is 783 nm thus indicating an optical bandgap of 1.58 eV, consistent with the reported values (1.55-1.61 eV) [A34]. For CsFA and CsFAMA perovskite thin films, the absorption onset blue (772 nm) and red (805 nm) shifted, resulting in band gaps of 1.53 eV and 1.60 eV, respectively. This is due to the different cations and halogens in the film. The band gap energy of organic-inorganic hybrid perovskites is inversely proportional to the cation size where cesium has the largest bandgap and formamidinium has the lowest bandgap [A33], The introduction of bromide into the films also increases the band gap slightly [A34], Figure 15 also shows PL spectra of the three different perovskite materials deposited on glass. PL peaks are observed at 780 nm, 796 nm, and 765 nm for the single, double, and triple cation perovskite structures, respectively.

[0337] The inset of Figure 15 shows time-resolved photoluminescence (TRPL) of the films and Table 1 shows detailed carrier lifetime parameters used to calculate the lifetimes. These parameters were obtained using a tri-exponential fitting equation [ A35 ]:

[0338] I

[0339]

[0340] (t) (1) where A; is the weight fraction of the PL decay lifetime component, τi. Both the intensity- (τavg,I) and amplitude- (τavg,A) average lifetimes were determined [A36],

[0341] The intensity-average lifetime is the average amount of time a fluorophore spends in an excited state. It is used in cases of collisional quenching described by Stern- Volmer relations [A36]. The intensity-average lifetime is determined using this equation:

[0342]

[0343] On the other hand, the amplitude-average lifetime is the lifetime a fluorophore would have if it had the same steady-state fluorescence as the fluorophore with several lifetimes. It is used in many cases, such as to estimate the energy transfer in Foster Resonance Energy Transfer (FRET) and to access dynamic quenching behaviors described by Stern-Volmer [A37], The amplitude-average lifetime is:

[0344] τavg,A= with Σ Ai= 1 (3)

[0345]

[0346] 10046-679W01: 8683 KOR TRPL data of the perovskite films deposited on glass substrates are shown in Figure 16. Both intensity- and amplitude- average lifetimes of the perovskite films were calculated and depicted in Table 1. A three-component exponential is needed to fully describe the fluorescence decay, where τ1, τ2, and τ3are contributions from excitons, electron-hole pairs, and free charge carriers, respectively [A38]. MAPI has the shortest τavg,Iof 60 ns with the highest weight of the fast decay component (A1), pointing to high nonradiative recombination. CsFAMA has an τavg,Iof 105 ns with the longest fast decay (τ1), indicating high intrinsic recombination and fewer defects at the surface compared to MAPI. The double cation films with CsFA exhibit the longest τavg,Iof 308 ns and show the longest slow decay (τ3) suggesting high-quality crystal formation with low defect density [A31], The significantly longer PL lifetime is consistent with the higher device performance observed for the CsFA films [ A39],

[0347] Table 1: TRPL lifetime fitting parameters using a tri-exponential decay, Eqn (1).

[0348] Ai T1 A2 T2 A3 T3 Tavg. I Tavg, A Sample on Glass (%) (ns) (%) (ns) (%) (ns) (ns) (ns) MAPbI394.3 30.1 5.33 81.8 0.35 489 59.4 34.5 Cs0.1FA0.9Pb(I0.95Br0.05)3 41.1 43.4 47.6 161 11.4 559 308 158

[0349]

[0350] Cs0.05FA0.79MA0.16Pb(I0.85Br0.15)3 44.1 13.7 39.1 54.4 16.8 164 105 54.9

[0351] SEM images of the different perovskite films showed that there are significant variations in film quality. Figure 16 shows representative images analyzed to obtain the crystal grain size and density of voids and pinholes. See Supporting Information, Figure 22, Figure 23, and Table 2. MAPI films exhibit a relatively large crystal grain size (228 nm), but with a significant number of pinholes and inhomogeneities. Cracks and voids occur throughout the film with 10.4% void density. As shown in Figure 16b and Figure 16e, the Cso.iFAo.9Pb(Io.95Bro.os)3 films had significantly fewer pinholes and no observable cracks. The void density of 2.3% was significantly lower than in the MAPI films. The crystal grain size was slightly smaller (181 nm). The triple cation, Cso.osFAo.79MAo.i6Pb(Io.85Bro.i5)3, films shown in Figure 16c and Figure 16d, also had a relatively low void density of 2.7% and similar crystal grain size of 180 nm. These differences in film characteristics are also apparent in the measured device performance. The double cation CsFA films are smooth with the fewest pinholes and lowest void density, exhibiting the highest Voc, Jsc, and PCE (Figure 14c, Figure 14d) of 247 V, 14.3 mA / cm2, and 1.16%, respectively, for the champion device.

[0352] The relative hydrophobicity of the perovskite films was also determined by contact angle measurements. As shown in Figure 17, the double cation CsFA films were the most hydrophobic. Contact angle of the MAPI, CsFA, and CsFAMA films varied from 77.0 °, 90.5 °, and 69.1 °,10046-679W01: 8683 KOR respectively. Existing studies suggest that higher hydrophobicity may yield improved durability [A35], To confirm the validity of this claim, an aging study of CsFA was performed where films maintained the perovskite a-phase for at least 3 weeks stored in ambient conditions (see Figure 24). The a-phase was still present after 9 months of storage in ambient conditions but mixed with some non-perovskite 5-phase. Moreover, films of MAPI and CsFA were exposed to air and rapidly heated to 210 °C.

[0353] Additionally, non-ambient aging was performed where MAPI, CsFA, and CsFAMA films were heated with temperatures ranging from 30°C to 450 °C under vacuum. The XRD of these films are shown in Figure 18, with zoomed in range around the perovskite (100) peak (29 = 14.0 °) and the lead iodide peak (20 = 12.7 °), as well as the full spectra depicted in Figure 25. Results show that CsFA is the most thermally stable film where the lead iodide peak started to emerge ~ 295 °C compared to -235 °C for both MAPI and CsFAMA films. Moreover, films of MAPI and CsFA were exposed to air and rapidly heated to 210 °C. Figure 26 shows some characteristic images of the films as they degrade and change color from black to yellow. MAPI turned completely yellow within 10 minutes, while CsFA took around 40 minutes to start turning yellow. The enhanced stability of CsFA could be attributed to the lattice strain due to Cs⁺ incorporation, which suppresses the migration of I⁻ thus mitigating the degradation of hybrid organic-inorganic perovskites [A40].

[0354] The effect of composition on the crystallinity of perovskite films was investigated using XRD, as depicted in Figure 19. The principal peaks of MAPI at 20 of 14.1°, 28.4°, and 31.8° correspond to (110), (220), and (310) planes of the tetragonal (P) phase of MAPbI3perovskite [A41, A42], The film is crystalline with sharp peaks. There is no evidence of residual PbI2. It is noted that CsFA and CsFAMA films exhibit characteristic peaks (100), (110), (111), and (200) of the perovskite a-phase at 20 values ~14.0°, 20.0°, 24.5° and 28.3° respectively [A24]. There is a weak diffraction peak at 12.7°, corresponding to PbI2since excess PbI2was added into the precursor ink. Moreover, as illustrated by Figure 19b, the peak position (110) shifted to higher 20 as per the increase of the Br content in the CsFAMA films compared to CsFA films, which implied a larger band gap for the material.

[0355] To further enhance device performance, the effect of PEAI treatment on CsFA devices was studied, and the results are depicted in Figure 20. PEAI was chosen due to its ability to modify the surface energy by optimizing the surface Fermi level as well as passivating the perovskite surface to reduce defect density [A40], Two different treatment procedures were studied, (1) treating the substrates with PEAI before active layer deposition, which is denoted as Pre-treat, and (2) treating the active layer with PEAI which is denoted as Post-treat. For this,10046-679W01: 8683 KOR different volumes of PEAI solution were spin-coated on the devices. Pre-treating the substrates with PEAI significantly enhances the Voc and Jsc of the devices, and it is directly proportional to the amount of treatment. On the other hand, a small amount of PEAI post-treatment enhances the Vocand then it starts to gradually drop with further additions of PEAI. However, there appears to be a tradeoff between the increase in Vocand Jscof the devices, where Jscgradually decreases with PEAI post-treatment. These results could be explained by the effect of treatments on the morphology of the perovskite films, which in turn affects the device performance. As shown in Figure 20b-Figure 20c, devices with no PEAI treatment have a non-uniform groove fill where the perovskite ink (visible as a light gray region) did not fill the whole groove. There are small voids observed at the bottom of the grooves which most likely result from trapped solvent remaining after ink deposition, or due to partial dewetting of the ink from the bare substrate at the bottom of the groove [A14]. A non-uniform coating along the length of the groove causes variations in the generated photocurrent [A12] and reduces the device shunt resistance [Al 3]. However, pre-treating substrates with PEAI increases the groove fill of the microgroove devices as shown by the absence of voids and the more uniform and complete filling of grooves with the perovskite ink. A possible explanation could be that PEAI is modifying the surface energy of the substrates, so the surface becomes more wettable, and thus ink fills the grooves more uniformly. Contact angle measurements (Figure 29) show that the substrate becomes more wettable and less hydrophobic when pre-treated with PEAI. This explains the enhanced photovoltaic performances of devices pre-treated with PEAI.

[0356] Conclusions. Perovskite composition affects the morphology of the films deposited on microgroove-patterned PET substrates and their corresponding PV performance. When deposited on back-contact flexible PSCs composed of micron-sized grooves, MA-free double-cation films with the formula Cso.o1FAo.9PbI2.85Bro.15 form highly uniform films of pure perovskite phase with minimal pinhole defects. The void density of double cation CsFA films was 2.28% compared to 10.4% and 2.66% for MAPI and CsFAMA, respectively. Moreover, CsFA films exhibited the longest TRPL lifetime of 308 ns, indicating a slower recombination of photogenerated carriers. The high contact angle of CsFA films of 90.5° indicates enhanced hydrophobicity, contributing to its improved structural stability. Therefore, Cso.o1FAo.9PbI2.85Bro.15 perovskite films should be used to overcome the instability issues of MA-containing films while enhancing the desirable properties of perovskites for solar energy conversion. Additionally, the application of PEAI as a pre -treatment to the transport layers promoted uniform coating along the length of the grooves and increased the groove fill, thereby enhancing the photovoltaic performances of the devices.

[0357] Experimental Methods10046-679W01: 8683 KOR Materials. Cesium iodide (CsI, 99.999% trace metal basis) was purchased from Thermo Fisher Scientific. Formamidinium iodide (FAI, >99.99%), methylammonium iodide (MAI, >99.99%), methylammonium bromide (MABr, >99.99%), and phenethylammonium iodide (PEAI) were purchased from Great Cell Solar. Lead bromide (PbBr2, 99.999% trace metal basis), dimethyl formamide (DMF, 99.8%, anhydrous), dimethyl sulfoxide (DMSO, 99.9%, anhydrous), A’-MethyI-2-pyrrolidone (NMP, 99.5%, anhydrous), acetonitrile (ACN, 99.8%, anhydrous), and ethyl alcohol (Eth, Pure 2.00 proof, >=99.5%, anhydrous) were purchased from Sigma Aldrich. Lead iodide (PbI2, 99.999% trace metal basis) was purchased from 'Tokyo Chemical Industry (TCI). Glass slides (Cardinal Health, plain microscope). Alconox detergent powder was purchased from Alconox. All chemicals were used without further purification.

[0358] Preparation of the perovskite films. Glass substrates cut into 2.5 cm x 2.5 cm pieces were cleaned by first sonicating in Alconox detergent (1 g in 100 mL of DI water) for 30 min, rinsed with DI water for 3 times, then sonicated in acetone then IPA for 30 min each. Substrates were dried with a nitrogen gun, exposed to UV ozone for 10 min and then transferred into the glovebox. All the following steps were performed in a nitrogen-filled glovebox. For all perovskite precursor solutions, 0.8 M solutions were prepared in a mixture of solvents DMF / Ethanol (4:1 v / v). The MAPI solution was prepared by mixing 1:1:1 molar ratio of PbI2 / MAI / NMP. The CsFA solution is comprised of FAI, PbI2, PbBr2, CsI, and NMP in the molar ratio 0.93:1:0.08:0.07:0.93 to obtain Cso.iFAo.9Pb(Io.95Bro.o5)3. Similarly, the CsFAMA solution is comprised of FAI, PbI2, PbBr2, CsI, MABr, and NMP in the molar ratio 0.66:0.71:0.15:0.04:0.13:0.66 to obtain Cso.o5FAo.79MAo.i6Pb(Io.85Bro.i5)3. The mixed solutions were magnetically stirred at room temperature for 1-2 h to obtain transparent bright-yellow solutions. The solutions were finally filtered with a 0.2 μm PTFE filter before use. Perovskite films were deposited by dropping 200 μL of precursor solution onto the center of the substrate while spinning at 3000 rpm for 30 s. Films were then annealed at 100°C for 10 min.

[0359] Substrate Fabrication. Polyethylene terephthalate (PET) substrates were micro¬ embossed roll-to-roll using a continuous UV casting process creating individual units / panels (100 mm X 100 mm) of micro-groove cascades. These rolls of embossed material were then coated roll-to-roll via e-beam and thermal evaporation. Glancing angle deposition was utilized to deposit the conductive, HTL and ETL layers on either side of the microgroove wall.

[0360] Device preparation. Individual units / panels were harvested from the roll format and cut into 1-2 cm2mini-panels. These mini-panels were cleaned under an air stream. Perovskite ink (50 μL) was spin-coated (3000 rpm, 30 s) on the substrates. The deposited nanocrystal film was then treated with PEAI solution (0.5 mol% in ACN). 'The substrates were then annealed at 100°C10046-679W01: 8683 KOR for 10 min.

[0361] Materials and Device Characterization. Absorbance and absorptance spectra were collected on a Cary 5000 UV-VIS NIR Spectrometer in double beam mode with a cleaned and UV-ozone treated bare glass substrate used for baseline. Absorptance, A, is related to the absorbance, Abs, of the sample as A — 1 — 10”j4&s. PL emission spectra and TRPL lifetimes were measured using a pulsed laser spectrometer with λexc= 532 nm at room temperature.

[0362] Scanning electron microscopy (SEM) was performed with an Apreo 2C LoVac SEM operated at 3 kV. X-ray diffraction (XRD) data for perovskite films were acquired on a Rigaku ULTIMA IV Diffractometer operated at 40 kV and 44 mA with Cu Ka radiation (λ=1.54 Å). Water contact angles to determine the hydrophobicity of the films were obtained using FTA200 Contact Angle Goniometer. Current-voltage scans were obtained from the devices using a Keithley 2400 General Purpose Source meter with a microprobe station. Geometric PCE and Jsc values are diminished as the microprobe station did not have high powered solar lamp with AM 1.5 filter.

[0363] Supporting Information.

[0364] Figure 21: Band gap determined from Tauc plots of the single, double and triple cation perovskite films and proposed band alignment with the electron and hole transport layers.

[0365] Figure 22: SEM images of perovskite films and determination of areal void fraction. Table 2: Void densities of the single, double, and triple cation perovskite films on microgroove substrates.

[0366] Table 2: Void densities of perovskite layers determined from Figure 22.

[0367] Image Area Total Void Area Void Density Film Composition (pm)2(pm)2(%)

[0368] MAPbI3545 56.9 10.44

[0369] Cs0.1FA0.9Pb(I0.95 / Br0.05)3 545 12.4 2.28

[0370]

[0371] Cs0.05FA0.79MA0.16Pb(I0.85 / Br0.15)3 545 14.5 2.66

[0372] Figure 23: SEM images of perovskite thin films on microgroove solar cells and crystal grain size distribution.

[0373] Figure 24: XRD patterns of Cs0.1FA0.9Pb(I0.95Br0.05)3 films within 9 months of exposure to air at an average room temperature of 25 °C and 30% RH.

[0374] Figure 25: Non-ambient aging XRD with temperatures ranging from 30°C to 450 °C under vacuum for different perovskite films.

[0375] Figure 26: XRD of Cs0.1FA0.9Pb(I0.95 / Br0.05)3 films after 6 weeks in air at 25 °C and 30% RH.

[0376] Figure 27: Images of MAPbI3and Cs0.1FA0.9Pb(I0.95 / Br0.05)3 films heated at 210 °C in air.10046-679W01: 8683 KOR Figure 28: PL spectra of CSxFAiJPb(Ii-yBry)3 perovskite films.

[0377] Figure 29: The water contact angles of a bare PET substrate patterned with microgrooves (a) before and (b) after PEAI treatment.

[0378] Figure 30. Photovoltaic performance from 8 flat cells with Cs0.1FA0.9Pb(I0.95 / Br0.05)3 films measured under simulated AM 1,5G illumination.

[0379] Tauc plots of the different perovskite films. Absorbance spectra of the perovskite films consisting of different compositions were recorded. From these data, the wavelength (I) was converted to energy E (eV) - 1240 / 1. The absorbance coefficient a = 2.303* Log (Absorbance). Absorptance was determined through the following equation: Absorptance = 1 - i0'Absorbance. The optical band gap (Eg) of each film was determined from Tauc plots of the absorbance spectra (ahu)2= A(ho-Eg). Where: a is the absorption coefficient, h the Planck’s constant, u the incident photon’s frequency, and A proportionality constant. Eg was determined by taking the slope of (ahu)2versus Energy [A44],

[0380] The band gap alignment of the different perovskites was determined using the conduction band energy (ECb) as previously reported [ A45], the band gap energy (Eg) calculated from the Tauc plots, and the valence band energy (EVb) using the formula Eg= ECb-EVb.

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[0425] (A35) Feng, Y. et al. Optical Properties of CsFAMA-Based Perovskite Film and Its Application in the Inverted Solar Cells with Poly(Methyl Methacrylate) Passivation Layer. Opt Mater Express 2022, 12 (8), 3262. https: / / doi.org / 10.1364 / ome.463437.

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[0430] (A39) Dequilettes, D. W. et al. Photoluminescence Lifetimes Exceeding 8 Ms and Quantum Yields Exceeding 30% in Hybrid Perovskite Thin Films by Ligand Passivation. ACS Energy Lett 2016, 1 (2), 438-444. https: / / doi.org / 10.1021 / acsenergylett.6b00236.

[0431] (A40) Zhang, Y. et al. Cesium Methylammonium Lead Iodide (CsxMAl-xPbI3) Nanocrystals with Wide Range Cation Composition Tuning and Enhanced Thermal Stability of the Perovskite Phase. Angewandte Chemie - International Edition 2023, 62 (31). https: / / doi.org / 10.1002 / anie.202306005.

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[0436] (A45) Blackburn, D. et al. Back-Contact Perovskite Solar Cell Modules Fabricated via Roll-to-Roll Slot-Die Coating: Scale-Up toward Manufacturing. ACS Appl Energy Mater 2025. https: / / doi.org / 10.1021 / acsaem.4c02734.

[0437] Example 6 - Multifunctional Ammonium Additive for Enhanced Efficiency and Stability of Perovskite Solar Cells

[0438] Abstract. The addition of dodecylammonium iodide (DAI) directly into the perovskite ink is an important strategy for defect passivation in perovskite solar cells (PSCs). Here, different concentrations of DAI were introduced into the PSCs precursor solution to research its influence on the perovskite films and the photovoltaic performance of PSCs. As a result, optimal concentration (2 mg / mL) of DAI results in a significant increase in the perovskite grain size, maintains the desired perovskite a-phase, and enhances the hydrophobicity of the perovskite film. DAI additive attaches to the surface of the perovskite film and doesn’t incorporate inside the perovskite lattice structure. This enhanced device performance of both plastic microgroove solar cells and flat cells where devices with DAI showed enhanced efficiency achieving a PCE of 4.34% and 16.5%, respectively.

[0439] Introduction. Perovskite solar cells (PSCs) have evolved tremendously over the past decade. To date, the highest certified power conversion efficiency (PCE) has surpassed 26% [Bl, B2] indicating a promising future for PSC photovoltaics commercialization. However, their commercialization is still limited by its poor device stability [B3]. The primary causes of this instability are the poor perovskite crystallinity as well as the presence of surface defects which are predominantly located at the surface and grain boundaries of the perovskite films [B4]. These defects function as traps leading to non-radiative carrier combination which decreases the PCE and operational stability of PSCs [B5, B6]. Thus, precise control of perovskite crystallization and effective defect passivation are crucial for further improving PSC device performance [B7].10046-679W01: 8683 KOR To overcome this, various strategies were adopted such as additive engineering [B 8 ], solvent engineering [B9], compositional engineering [B10-B12], and interface engineering [B 13-B 15]. Among them, additive engineering is the most effective approach as minor additive quantities could drastically change the drying process of the perovskite precursor and smooth the surface of the perovskite film.

[0440] Additive engineering can be accomplished in two paths [B4, B16, B 17]: either (1) added directly into the perovskite precursor solution, or (2) as a post processing step after the film formation. In the first case, additives will interact with perovskite precursor solution and form adducts which control the perovskite crystallization and may result in better film quality [B4]. These additives could either volatilize during film formation or coordinate to the perovskite grain surfaces and passivate the surface defects [Bl 8], For example, the addition of 4-fluorobenzamide to the FAPbL perovskite ink regulated the crystal growth and resulted in high quality films [B 19]. The addition of di-n-butyl sulfoxide (DBSO) was found to suppress the undesirable perovskite 5-phase and resulted in a larger grain size [B20]. On the other hand, when additives are used as post treatment material, it could no longer alter the internal crystallization process and will only passivate the surface defects [B20].

[0441] Various additives with different functional groups have been studied; among them, amino and ammonium functional groups have shown superior effects on improving material properties and enhancing device performance [B21], These additives tend to interact with the perovskite through Lewis acid-base interactions, where Pb2+is the Lewis acid with a d orbital that can accept a lone pair [B22]; or through hydrogen bonding between ammonium hydrogen atoms and halides from the perovskite [B14, B 15]. For example, -aminovaleric acid halides (5-AVAX) can passivate multiple defect types through Lewis acid-base coordination and hydrogen-bonding interactions which enhances the device performance and stability [B23, B24], Wang et al. showed that ammonium salt aggregate at the surface of the perovskite film and grain boundaries which could facilitate the charge transport and thus enhance device performance [B25]. Zhou et al. showed that introducing dodecylammonium bromide (DDABr) surfactant into the perovskite MAFAPbI3 precursor solution promoted grain growth and assembled on the surface of the perovskite film which improved film stability and device performance [B26]. Similarly, adding dodecylammonium chloride (DCl) into the perovskite Cs3Bi2I9 resulted in improved crystallinity of thin films and better photovoltaic devices [B27],

[0442] Herein, dodecylammonium iodide (DAI) additive was introduced into the perovskite Cso.iFAo.9Pb(Io.95Bro.o5)3 ink which could modify the precursor crystallization dynamics and promote the grain growth. The introduction of small amounts of DAI could stabilize the10046-679W01: 8683 KOR perovskite a-phase and enhance device performance. Moreover, the hydrophobic chain group of the DAI surfactant could self-assemble on the surface of the perovskite film and thus hinder the penetration of water into the perovskite film, enhancing the stability of the device. Therefore, the champion device with optimal concentration of DAI additive reached a PCE of 16.5% with an aperture area of 16.6 mm2.

[0443] Results and Discussion. Ammonium additive DAI with varying concentrations (0 — 10 mg / mL) was incorporated into the perovskite precursor solution (Figure 31a). The perovskite films were blade coated on all back contact plastic solar cells fabricated on polyethylene terephthalate (PET) substrates embossed with micrometer-scale grooves. The electron and hole transport layers are on opposing sides of the grooves and are composed of a Ti / SnO2 / C60 multilayer and Ni / NiO, respectively, as depicted in Figure 1b. The nitrogen air knife assisted in the film drying dynamics and nucleation crystallization process during blade coating of the perovskite film (Figure 31c).

[0444] SEM images of Cso.iFAo.9Pb(lo.95Bro.o5)3 with different concentrations of DAI additives are shown in Figure 32 and analyzed to obtain grain size. There is a significant increase in the grain size with increasing the concentration of DAI additive in the perovskite ink. Average grain size increased from 138 nm when no additive is used to 279 nm when 10 mg / mL of DAI was added. Additives coordinate with the precursor solution to form intermediate adduct which regulates crystallization kinetics; accelerates nucleation and control the rate of crystal growth, resulting in larger grain sizes [B4], This increase in grain size is often coupled with a decrease in grain boundary area, which suggests a decrease in the density of trap states as the grain boundary area decreases [B4, B28]. Additionally, grain size affects how stable perovskite films are to moisture in humid conditions; films with bigger grains retain more PCE than those with smaller grains [B4, B29].

[0445] Moreover, the effect of additive concentrations on the crystallinity of the perovskite films was investigated using XRD, as depicted in Figure 33. The principal peaks of Cso.iFAo.9Pb(Io.95Bro.o5)3 at 29 values ~14.0°, 20.0°, 24.5° and 28.3° correspond to (100), (110), (111), and (200) planes of the perovskite a-phase, respectively. Excess Pbh was added into the precursor ink, and this corresponds to the weak diffraction peak at 12.8° (001) [B30], When the additive concentration exceeds 2 mg / mL of DAI in the perovskite ink, there is a noticeable formation of the hexagonal non-perovskite yellow phase of FAPbL (i.e., S-FAPbL) [B30] which is characterized by a dominant peak at 20 of 11.8°. This means that 2 mg / mL is the maximum limit of adding DAI additive into the perovskite ink while maintaining the desired perovskite a-phase. Moreover, no diffraction peak was observed at 7.3°, this eliminates the potential10046-679W01: 8683 KOR formation of a 2D perovskite layer [B30]. Grätzel et al. showed that the addition of an amino additive crosslink neighboring grains, stabilizing the α-FAPbI3 perovskite and inhibiting the a-to-5 phase transition [B23J.

[0446] To understand the reason behind the phase change at concentrations higher than 2 mg / mL, PL of Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite films with different DAI concentrations are measured and depicted in Figure 34. A focus was on low concentrations (0, 1, and 2 mg / mL) as well as very high concentrations (10 mg / mL) of DAI. There is a noticeable PL peak shift from 784 nm when low concentrations of DAI are used, to a PL peak of 788 nm for 10 mg / mL. of DAI. This red PL shift could be explained by the halide exchange [B31] between the additive and the perovskite. The iodide in the DAI could be partially replacing the bromide in the Cso.iFAo.9Pb(Io.95Bro.o5)3 structure. Small amounts of bromide are needed to stabilize the perovskite (a) phase, as the ratio between the halides dictates the final structure of the perovskite [B32, B33]. Thus, this change in the bromide concentration could be attributing to the formation of the hexagonal non-perovskite yellow phase (5) for concentrations higher than 2 mg / mL, of DAI as shown earlier in the XRD (Figure 33).

[0447] XPS was performed to determine how the DAI additive interacts with the perovskite, whether it’s passivating the surface or incorporating into the perovskite bulk lattice. DAI additive has a protonated amine group (R-NILA) as a functional group, while the perovskite has an amine group due to the formamidinium nitrogen (C(=NH)-NH2+). The presence of these two amine groups is evident from the N1sspectra shown in Figure 35a. Two peaks with a binding energy region 400.8 and 402.3 eV are present in the films that contain DAI additive, while only one peak (402.3 eV) is present in the control film. The standard binding energy for the free amine group falls in the region of 399-401 eV, while the protonated amine has a higher binding energy of 1.5 eV above the free amine [B34, B35]. Thus, the peak at 400.8 eV is assigned to the (C(=NH)-NH2+) corresponding to C-N from FA+of perovskite [B36] while the peak at 402.3 eV is attributed to protonated amine groups of the additive (R-NH3+). After sputtering and the removal of surface composition, only one peak was left which corresponds to C-N from the perovskite as seen in Figure 35b. This proves that DAI additive is attaching to the surface and not being incorporated inside the perovskite lattice structure. Figure 36 shows a schematic of this proposed behavior of DAI additive. It’s important to note here that sputtering doesn’t have a drastic effect on the chemical modification of the perovskite layer, thus validating the determination of the in-depth composition of the layer [B36].

[0448] The presence of DAI additive on the surface of the perovskite films can be further justified by the water contact angles, as shown in Figure 37. Contact angle increases from 66.50°10046-679W01: 8683 KOR to 76.46°, 76.55°, 77.30°, 82.04°, 82.32°, 83.00°, 84.04°, 84.75°, 87.63°, and 92.63° as the concentration of DAI additives increases from 0 mg / mL to 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, 5, and 10 mg / mL, respectively. The more DAI is added, the more hydrophobic the surface becomes. Therefore, the hydrophobic group of the ammonium additive, which is self-assembled on the film surface pointing to air, could hinder the penetration of water into the perovskite film and thus could improve the film and device stability [B37].

[0449] To test the effect of DAI on the performance and stability of Cs0.1FA0.9Pb(I0.95Br0.05)3 perovskite, solar cells were fabricated using the back contact plastic solar devices mentioned above. Figure 38 shows a boxplot of the efficiencies of a total of 146 solar cells fabricated with different additive concentrations and having an active area of 7.92 mm2. The addition of DAI increases power conversion efficiency from an average of 1.54 % to 4.34 % when 2 mg / mL of DAI was added to the perovskite ink; adding higher concentrations causes the efficiencies to drop again. This is explained by the phase change of the perovskite into a hexagonal non¬ perovskite phase with higher concentrations (> 2mg / mL) of DAI as proved earlier. It should be noted here that all the characterizations that were performed on spin coated perovskite films are transferable to the blade coated solar cells as shown in Figure 39. Both spin coated and blade coated solar cells have a similar average grain size of about 133.4 - 137.6 nm.

[0450] To validate the impact of DAI, perovskite thin films were prepared with (2 mg / mL) and without DAI and fabricated solar cells with an n-i-p architecture of FTO / TiCh / Perovskite / spiro-OMeTAD / Au as shown in Figure 40a. The device had an active area of 0.166 cm2. 22 devices were fabricated each with and without DAI and the efficiency distribution was statistically analyzed as shown in Figure 45. The champion device from the perovskite with DAI achieved a maximum efficiency of 16.5% with a Vocof 0.73 V, Jscof 44.8 mA.cm-2, and FF of 50%. The J-V curve and photovoltaic parameters under forward and reverse scans are depicted in Figure 40b-Figure 40c. Adding DAI into the ink enhanced the efficiency from 13% to 16.5%. Moreover, Figure 40d shows the stabilized power output (SPO) of the device held at a bias voltage of maximum power point (0.579 V) tracking under simulated 1 sun illumination. The SPO of both devices persisted in a short time aging, where the Jsc stayed above 1.8 mA.cm-2and 16.9 mA.cm-2for devices without and with DAI, respectively.

[0451] Conclusions. In summary, DAI was introduced as an additive into the perovskite precursor ink at different concentrations and it was found that 2 mg / mL is the optimal amount to be added. This resulted in an increase of the grain size from 138 nm to 196 nm while maintaining the desired perovskite a-phase. Adding more DAI resulted in halide exchange between the I' of DAI and the Br~ of the perovskite which attributes to the formation of the10046-679W01: 8683 KOR hexagonal non -perovskite yellow phase (5). Moreover, it was shown that DAI additive is attaching to the surface of the perovskite film and not being incorporated inside the perovskite lattice structure. This results in a more hydrophobic perovskite film. Furthermore, devices with DAI showed enhanced efficiency achieving a PCE of 4.34% for doctor-bladed microgroove devices and 16.5% flat cells.

[0452] Experimental Methods

[0453] Materials. Cesium iodide (CsI, 99.999% trace metal basis) was purchased from Thermo Fisher Scientific. Formamidinium iodide (FAI, >99.99%), Methylammonium chloride (MACl, >99.99%), and n-Dodecylammonium iodide (DAI, >99%) were purchased from Great Cell Solar. Lead bromide (PbBr2, 99.999% trace metal basis), dimethyl formamide (DMF, 99.8%, anhydrous), dimethyl sulfoxide (DMSO, 99.9%, anhydrous), 4-tert-Butylpyridine (TBP, 98%), Bis(trifluoromethane)sulfonimide lithium salt (Li-TFSi, 99.95% trace metal basis), Spiro-MeOTAD (>99.5%), Titanium diisopropoxide bis(acetylacetonate) (TiAcAc, 75w% in isopropanol), Zinc powder (<150 pm, 99.995% trace metal basis), 1 -Butanol (anhydrous, 99.8%), Chlorobenzene (anhydrous, 99.8%), Acetonitrile (anhydrous, 99.8%), 2 -Propanol (IPA, laboratory reagent, >99.5%), and Acetone (ACS reagent, >99.5%) were purchased from Sigma Aldrich. Lead iodide (PbI2, 99.999% trace metal basis) was purchased from Tokyo Chemical Industry (TCI). Hydrochloric acid (HC1, 37% ACS grade) was purchased from Avantor Science Central (VWR). Glass slides (Cardinal Health, plain microscope) and Fluorine-doped tin oxide (FTO) glass (Ossila, 11-13 Q / sq). Alconox detergent powder was purchased from Alconox. All chemicals were used without further purification.

[0454] Preparation of the perovskite films. The fabrication of perovskite films was performed in a nitrogen-filled glovebox. 0.8 M Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite solution was prepared by mixing FAI (0.81 mmol), PbI2 (0.83 mmol), PbBr2 (0.07 mmol), CsI (0.09 mmol), and MAC1 (0.09 mmol) in a mixed solvent of DMF / DMSO (9:1 v / v ratio). For perovskite with DAI additive, different concentrations of DAI in DMF were added to the perovskite solution to obtain (0, 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, 5, and 10 mg / mL) solutions. The mixed solutions were magnetically stirred at room temperature for 1 hr to obtain transparent bright-yellow solutions. The solutions were finally filtered with a 0.2 μm PTFE filter before use.

[0455] The solution for the hole transporting layer (HTL) was prepared by dissolving 72 mg Spiro-MeOTAD, 28.8 pLTBP and 17.5 pL Li-TFSi solution (520 mg Li-TFSi in 1 ml acetonitrile) into 1 ml chlorobenzene.

[0456] Fabrication of microgroove perovskite devices. Individual units / panels (100 mm x 100 mm) of micro-groove cascades were created by roll-to-roll micro-embossing of polyethylene10046-679W01: 8683 KOR terephthalate (PET) substrates using a continuous UV casting process. These rolls of embossed material were then coated roll-to-roll via e-beam and thermal evaporation. The conductive, HTL, and ETL layers were deposited on either side of the microgroove wall using glancing angle deposition. Individual units / panels were harvested from the roll format and cut into 33 mm width strips. These strips were cleaned under an air stream. Perovskite film was blade coated on the substrates with a blade speed of 20 mm / s, blade height of 200 nm, and air knife (2.5 SCFM). The substrates were then annealed at 100°C for 10 min.

[0457] Fabrication of flat cell perovskite devices. FTO glass was patterned by partially etching of the conductive layer by using hydrochloric acid (35 wt%) and Zinc powder. A thorough cleaning was carried out by washing the FTO substrate with Alconox detergent (lw%), deionized water, acetone, and isopropyl alcohol in sequence order under sonication for 10 min. Substrates were dried with a nitrogen gun and exposed to UV ozone for 20 min to remove organic residuals. Electron transport layer (ETL), TiO2, was deposited onto FTO substrate via spin coating a 0.15 M filtered (0.45 mm PTFE) solution of TiAcAc in 1-butanol at 2000 rpm for 40 s. The film was sintered at 500 °C for 10 min in air. Before being transferred to a nitrogen filled glove box, the film was exposed to UV-Ozone for 20 mins to clean the surface.

[0458] The perovskite layer was deposited onto the TiO2layer by a two-step spin coating program consisting of 1000 rpm for 10 s followed by 4000 rpm for 35 s, while dripping 185 uL chlorobenzene onto the spinning substrate at the 20th s during the second step. The perovskite layer was then annealed at 100 °C for 40 min on a hot plate. After cooling down to room temperature, HTL was deposited by spin coating the Spiro-MeOTAD solution on the perovskite film at 4000 rpm for 60 s. The substrates were then taken out of the glovebox, wrapped in aluminum foil, and allowed to sit in the desiccator overnight to make the HTL more conductive. Finally, the device fabrication was finished by depositing a 100 nm gold layer on the prepared film as the back contact electrode through an e-beam evaporation process at 2 x 10-5Torr pressure.

[0459] Characterization. Scanning electron microscopy (SEM) was performed with an Apreo 2C LoVac SEM operated at 3 kV. X-ray diffraction (XRD) data for perovskite films were acquired on a Rigaku ULTIMA IV Diffractometer operated at 40 kV and 44 mA with Cu Ka radiation (λ=1.54 Å). PL emission spectra were measured using a pulsed laser spectrometer with λexc =532 nm at room temperature. X-ray Photoelectron Spectrometry (XPS) was measured using a Kratos AXIS Ultra DLD photoelectron spectrometer. Water contact angles to determine the hydrophobicity of the films were obtained using FTA200 Contact Angle Goniometer.

[0460] Current- voltage (J-V) plots of perovskite solar cells were obtained under irradiation of 10010046-679W01: 8683 KOR mW / cm2(AM 1.5, 1 sun) using a solar simulator (Keithley 2400 General Purpose Source meter) equipped with 450W Xenon lamp.

[0461] Supporting Information,

[0462] Figure 41: The molecular structure of dodecyl ammonium iodide (DAI).

[0463] Figure 42. Band gap determined from Tauc plots for perovskite films with and without DAI additive.

[0464] Figure 43. XPS spectra for perovskite films with and without DAI additive.

[0465] Figure 44. Boxplots of photovoltaic parameters for a total of 146 microgroove solar cells fabricated with Cso.iFAo.9Pb(Io.95Bro.o5)3 perovskite with different concentrations DAI additive.

[0466] Figure 45. Photovoltaic parameters statistics of 22 devices each with and without DAI additive.

[0467] Figure 46. Photographs of perovskite films heated at 210 °C in air for 0 min, 25 min, 35 min, 45 min, and 105 min.

[0468] Figure 47. Non-ambient aging XRD of Cso.iFAo.9Pb(Io.95Bro.os)3 perovskite films with and without DAI additive under nitrogen at temperature 210°C.

[0469] Figure 48. XRD patterns of perovskite films with and without DAI additive under exposure to air at an average room temperature of 25°C and 30% RH.

[0470] Figure 49. XRD patterns of perovskite films with and without DAI additive aged at temperature of 50°C and 50% RH.

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[0514] Example 7 - Ambient Blade Coating of Multi-Cation Perovskites with Green Solvents on Plastic Microgroove Photovoltaic Devices

[0515] ABSTRACT. Large-scale deposition of high-quality perovskite films onto photovoltaic devices requires ink formulations that balance optimal coating dynamics with health, safety, and environmental considerations. Commonly used solvents for perovskite coatings, such as dimethyl formamide (DMF) or n-methyl-2-pyrrolidone (NMP), can lead to high-quality films, but are toxic, hazardous, and dangerous to the environment. Here, a perovskite ink based on10046-679W01: 8683 KOR dimethyl sulfoxide (DMSO) as the primary coordinating solvent and acetonitrile (ACN) as a cosolvent is reported that allows for a lower-toxicity ink with tunable viscosity and vapor pressure (Figure 50). Systematic solubility screenings of candidate green solvents established DMSO as the safest solvent able to fully dissolve precursor salts used in double cation perovskite inks, while dilution with ACN allowed for tunable ink properties without compromising precursor solubility. PV devices are made via air knife-assisted blade coating Cso.iFAo.gPbHcwsBro.osh into micrometer-scale grooves of a flexible interdigitated back contact substrate with n- and p-type transport layers thermally deposited on opposite groove walls. Device performance and uniformity are explored using electrical characterization under simulated sunlight and scanning electron microscopy. A 0.9 M 2:1 (v / v) ACN: DMSO perovskite ink is blade coated onto 30+ cm2device areas in ambient conditions with an optimized air-knife drying process to give groove cascades with performances surpassing 300 V open circuit voltage and 5% power conversion efficiency.

[0516] INTRODUCTION. Perovskite solar cells (PSCs) have emerged as one of the most promising photovoltaic (PV) technologies of the past decade. Their rapid development and potential for providing cheap and efficient solar power on a large scale has led to much progress towards commercialization. For PSCs to fully realize commercial potential, a set of interconnected manufacturing challenges that currently stand between laboratory-scale demonstrations and large-scale production must be addressed: the toxicity of the solvent system used to deposit perovskite films, the scalability of the processes, and the difficulty of achieving uniform coating on non-planar substrates. 'This work addresses these issues by introducing a new perovskite ink formulation based on acetonitrile (ACN) and dimethyl sulfoxide (DMSO) that was designed as a safer ink alternative capable of high-speed commercial coating applications.

[0517] The most widely used solvents for dissolving perovskite precursor salts and forming uniform films - dimethyl formamide (DMF) and n-methyl-2-pyrrolidone (NMP) - are highly effective coordinating solvents but carry significant health and environmental risks. Both solvents are classified as reproductive toxins and are subject to stringent manufacturing regulations. In contrast, DMSO is rated as “recommended” by the CHEM21 solvent selection guide across safety, health, and environmental metrics, while DMF and NMP are both classified as “hazardous.” DMSO is a commonly used solvent in pharmaceutical applications, most notably for topical creams, and is not hazardous to human health as a standalone chemical. DMSO is poorly suited for high-throughput perovskite film coatings due to low vapor pressure (0.42 mmHg) and relatively high viscosity (2 cP), which causes slow solvent evaporation and limits control over film morphology. In this work, ACN is used as a cosolvent to tune the10046-679W01: 8683 KOR rheological properties and evaporation of the ink to be more compatible with scalable deposition, while maintaining sufficient precursor solubility.

[0518] Significant progress has been made to develop mechanically flexible, lightweight PSCs over the last decade. Flexible substrates such as acrylic or polyethylene terephthalate (PET) are ideal candidates for meeting the demand for lightweight, easy to install, and cost-effective solar devices. However, the processing involved in fabricating PSCs on flexible substrates often faces challenges such as uniformity, pinhole formation, and mechanical robustness. PET substrates embossed with microgroove arrays offer an innovative platform to manufacture mechanically flexible and lightweight perovskite solar cells. Deposition of uniform perovskite layers onto topographically complex surfaces presents challenges related to film quality.

[0519] Microgroove architecture is a new device structure in which micron scale grooves are embossed onto a flexible roll of substrate (like polyethylene terephthalate, PET) and directional thermal deposition is used to stack electron and hole transport layers on opposing groove walls. The light absorbing material, such as perovskite, is deposited in the center of the grooves to complete the PV device. Electrically connecting neighboring grooves in series to create a cascade allows for tuning the voltage or current to a desired output by simply connecting the desired quantity of grooves together in series [C1-C3J.

[0520] One area of concern that must be addressed for commercial production of PSCs is the uniformity and quality of large-scale deposition of perovskite materials. Lab-scale deposition methods, such as spin coating, are not scalable [C4, C5]. Blade coating allows for deposition of thicker films with more control over morphology and can act as a steppingstone between lab-scale research and large-scale commercial production [C6-C9], The similarities between blade coating and conventional large-area deposition techniques such as slot-die coating allow for relatively easy adaptations to fit the need of various fabrication processes [C3, CIO, Cl 1 ].

[0521] The solvents identified here minimize risks in these areas while improving the coating behavior, film formation, and PV performance [C 12, C13]. ACN is rated as “recommended” by CHEM21, has a high vapor pressure (73 mmHg), low viscosity (0.35 cP), and has been previously demonstrated as a cosolvent for perovskite inks. While some ACN-based inks take advantage of highly coordinating cosolvents such as methylamine or 2-methoxyethanol with low vapor pressures, these cosolvents pose serious risk to health and safety. Mixing ACN with DMSO allows for tuning of the viscosity and vapor pressure while the coordinating character of DMSO maintains sufficient solubility of the precursor salt mixture. By using a safe and new mixture of solvents, the blade coating process was optimized and the potential for scalable high- performance PSC production is shown. This work paves the way for future innovations toward

[0522] 5 / 10046-679W01: 8683 KOR large-scale commercial production of efficient, cost-effective, and durable flexible PSCs.

[0523] Experimental Methods

[0524] Materials. Lead(II) bromide (PbBr2, 99.999% trace metals basis), acetonitrile (ACN, anhydrous, 99.8%), dimethyl sulfoxide (DMSO, anhydrous, >99.9%) were obtained from Sigma Aldrich. Formamidinium iodide (FAI, >99.99%), methylammonium chloride (MACl, >99.99%), and n-dodecylammonium iodide (nDAI) were purchased from Greatcell Solar Materials. Lead(II) iodide (PbI2, 99.99% trace metals basis) was obtained from Tokyo Chemical Industry and cesium iodide (CsI, 99.999%) was purchased from Thermo Scientific Chemicals. Microgroove-embossed PET substrates with deposited transport layers were obtained from Power Roll Ltd.

[0525] Perovskite Ink Preparation. Inside a nitrogen -filled glovebox, a 3 M stock solution of Cso.iFAo.9Pb(Io.9sBro.o5)3 with 10 mol% MAC1 additive is freshly prepared each day before use. Typically, 7.8 mg (0.03 mmol) CsI, 8.3 mg (0.022 mmol) PbBr2, 46.4 mg (0.270 mmol) FAI, 127.9 mg (0.277 mmol) PbI2, and 2.0 mg (0.03 mmol) MAC1 are added to 100 μL of DMSO in a 7 mL glass vial. The vial is capped and stirred on a hot plate at 80° C for 15 min. Separately, 10 mg of nDAI is dissolved in 1 mL of ACN at room temperature. The ink used for blade-coating is prepared by adding the appropriate volume of ACN (either with or without nDAI) and DMSO to the 3 M DMSO stock solution to obtain the desired concentration and ACN: DMSO volume ratio. Typically, 67 μL of the nDAI / ACN mixture, 155 μL ACN, and 11 μL DMSO are added to 100 μL of the 3 M stock solution to obtain 333 μL of 0.9 M Cso.iFAo.9Pb(Io.95Bro.o5)3 in 2: 1 ACN: DMSO with 10 mol% MAC1 and 2 mg / mL, nDAI additives.

[0526] Blade Coating. An MTI Corporation MSK-AFA-III Auto Matic Thick Film Coater was placed in a custom-built flow box purged with dry air to a relative humidity (RH) ranging between 6%-10%. The coater was equipped with an Exaire Super air knife set 3.5 cm above the platen surface with perpendicular orientation to the substrate (0° attack angle) to push the film applicator. The air knife was equipped with a footswitch-controlled solenoid valve for turning it on / off during coating. Dry N2was supplied to the air knife at a flow rate of 2.5 SCFM. For perovskite coating, the microgroove substrates were cut into 33 mm x 100 mm strips along the groove length (grooves span 100 mm length) and secured to the platen using Kapton tape. A Proceq ZUA 2000 universal film applicator was set to a 200 μm gap between the blade and top of the microgroove substrate. With the air knife off, the film applicator was set 1 cm before the active area of the substrate. 40 pL of ink was dispensed into the gap between the blade and substrate using a pipette. The air knife was then turned on and the applicator was set forward at the desired coating speed. Once the air knife stream reached the end of the coated substrate, it10046-679W01: 8683 KOR was returned to the starting position and then turned off. 'The coated substrate was removed from the platen and placed onto a 130° C hot plate and annealed for 8 min. The sample was removed from the hot plate, allowed to cool to room temperature, then prepared for characterization.

[0527] Material Characterization. UV-vis-NIR absorbance spectra were acquired using a Cary 5000 UV-VIS NIR spectrometer in single beam mode. PL spectra of perovskite films were measured on a Horiba Fluorolog3 Fluorometer with an excitation wavelength of 600 nm. X-ray diffraction (XRD) data for films was acquired using a Rigaku Ultima IV Diffractometer with a thin film attachment and operated at 40 kV and 44 mA with Cu Karadiation (λ= 1.54 Å) at a scan rate of 2.0 ° min. Scanning electron microscopy (SEM) images were collected on a Zeiss GeminiSEM 460 operated at 1.7 kV accelerating voltage and 100 pA probe current.

[0528] PV Device Characterization. Groove cascade devices comprising 362 microgrooves electrically connected in series were tested using a microprobe station equipped with tungsten probes with a 1 pm tip radius. PV devices were illuminated with an ABET Technologies 10500 Solar Simulator with a 150 W Xenon arc lamp calibrated to 1 sun illumination using a Hamamatsu SI 787-12 Silicon Photodiode. Current- voltage sweeps were performed using a Keithley 2470 source-measure unit.

[0529] RESULTS AND DISCUSSION. Many of the solvents used to dissolve perovskite precursors pose significant safety risks and are toxic to health and the environment. Scaling up perovskite deposition processes will be made more viable if a less toxic and more environmentally friendly alternative perovskite ink solution is used. Dimethyl formamide (DMF), n-methyl-2-pyrollidone (NMP) and dimethyl sulfoxide (DMSO) are coordinating solvents that are commonly used to dissolve the reactants used to deposit lead halide perovskite films [Cl 2]. Several solvents are explored and their safety, health and environment scores from the CHEM21 solvent guide are depicted in Table 3 [C 14].

[0530] Cyrene, anisole, 2-methltetrahydrofuran (2ME-THF), and g-valerolactone (GVL) were chosen due to their lower toxicity than remaining solvents and are considered green. It is also important for the solvent to be able to dissolve the perovskite precursors at a concentration >0.6 M to be suitable for film deposition. Thus, the solubility of Cso.iFAo.9Pb(Io.95'Bro.o5)3 precursors in each solvent was studied, as shown in Figure 51a. None of CsI, MACl, PbBr2and PbI2, are soluble at 0.6 M, with the exception of FAI, which dissolved in GVL. Images for each solvent and concentration (1.2M, 1.0M, and 0.6M) studied here can be seen in Figure 56. Yellowing of the solutions was apparent with iodine-containing salts, CsI, FAI, and PbBr2, especially with the solvents Cyrene and 2ME-THF. This is an indication of I-oxidation into I2.10046-679W01: 8683 KOR Table 3. Solvent properties along with safety, health, and environmental safety scores from CHEM21 solvent guide [C 14] with corresponding rankings for solvents in this study. Scores and rankings are shown; scores 1-3 (recommended), 4-6 (problematic), and 7-9 (hazardous), respectively.

[0531] Vapor CHEM21 Solvent Guide Score [C14]

[0532] Viscosity Pressure

[0533] Chemical (centipoise) (mmHg) Safety Health Environment Ranking DMF 0.9 2.6 3 9 5 Hazardous NMP 1.65 0.3 1 9 7 Hazardous DMSO 2 0.42 1 1 5 Recommended Cyrene 14.5 0.09 1 2 7 Problematic Anisole 1.52 2.4 4 1 5 Recommended 2ME-THF 0.6 102 6 5 3 Problematic GVL 1.9 0.32 1 5 7 Problematic

[0534]

[0535] ACN 0.35 73 4 3 3 Recommended

[0536] It is apparent that these alternative solvents cannot solely dissolve the necessary precursors and therefore DMSO was reintroduced as the main coordinating solvent. Figure 5 lb shows dilutions of Cso.iFAo.9Pb(Io.95Bro.o5)3 at various volume fractions and concentrations with Cyrene, anisole, 2ME-THF and GVL used as the cosolvent diluent. Cyrene and GVL were used to dilute the concentrated DMSO Cso.iFAo.gPbOo.ssBro.os)’ ink without visible formation of solid precipitation or F formation. However, anisole caused the solution to become turbid once more than 50% v / v was added. Also, 2ME-THF caused the solution to develop an orange hue, indicative of I2formation. While Cyrene and GVL appeared to be potential cosolvents candidates to be used with DMSO, further considerations of solvent properties are necessary to obtain a solution with optimal coating properties.

[0537] Film coating processes are sensitive to solution properties such as viscosity and volatility. Figure 5 Id shows a plot of vapor pressure vs. viscosity. Large area, high throughput roll-to-roll manufacturing benefits from ink solutions with low viscosity and high vapor pressure. Mixing acetonitrile (ACN) with DMSO allows for tuning the viscosity and vapor pressure of the ink in the optimal range [C 15]. Different volume ratios of ACN: DMSO (X: Y) were explored. It was found that a mixture of 2:1 ACN: DMSO by volume was optimal for blade coating microgroove devices. It is also important to note that the solubility limit for the perovskite composition used here is about IM at 2:1 ACN: DMSO. This limit is mostly determined by the amount of precursor salts that can be dissolved in neat DMSO. It was found that a 3M solution of Cso.iFAo.9Pb(Io.95Bro.o5)3in neat DMSO can be prepared with stirring and moderate heating (~80°C). This 3M solution can then be diluted to the desired solvent ratio and concentration, as depicted in Figure 5 le. Ink compositions above the solubility line were achieved by dissolving10046-679W01: 8683 KOR the precursors at concentrations greater than 3M in DMSO. However, it was common for solids to precipitate out of solution once cooled or upon dilution with ACN.

[0538] Figure 52a shows the optical properties of a Cso.i o.9Pb(Io.95Bro.o5)3 film deposited on glass. A broad absorbance profile was observed with the onset around 840 nm and a strong shoulder around 780 nm. The photoluminescence (PL) spectra shows a well-defined emission peak at 790 nm. Tauc plot of this data (Figure 57) shows a bandgap of -1.54 eV. The optical properties of our Cso.iFAo.9Pb(lo.95Bro.o5)3 film are consistent with those of similar materials, such as FAPbL [Cl 6], Additionally, XRD data for our film deposited onto microgroove substrate is seen in Figure 52b. The film is mostly a-FAPbh with a small amount of S phase FAPbL indicated by the (100) peak at 12° 29. The broad peak centered at 26° 20 is from the underlying PET substrate.

[0539] Optimization of the blade coating process was performed primarily on the blade speed and air knife settings [C17-C19], Figure 53a shows three microgroove substrates coated at 16 mm / s, 33 mm / s, and 50 mm / s blade speed photographed on a checkered background to highlight opacity of the resulting devices. The ink used in these trials was 0.6M with a solvent ratio of 4: 1 (v / v) ACN: DMSO. Faster blade speeds lead to less transparent films. Top-down SEM images show similar' perovskite grain formation and defects amongst the different coating speeds, seen in Figure 53b-Figure 53d. Holes on the scale of 100 nm are seen throughout the perovskite films formed within the grooves. Larger gaps that span the width of the microgroove where the film did not form together can also been seen for all coatings.

[0540] Cross-sectional SEM shows the difference in film thickness for devices coated at 16 mm / s and 50 mm / s, as depicted in Figure 53f. The microgrooves coated at 16 mm / s are only about one third filled with perovskite. In contrast, the 50 mm / s coated microgrooves are more than halfway filled. Faster coating speeds led to overfilling of the microgrooves, which is detrimental to device performance. Figure 53e shows the device current density-voltage sweeps for each of the three coating speeds. Most notably, the short circuit current increases with blade speed and groove fill. This is likely due to more charge extraction from more perovskite material in the microgrooves. The PCEs of the three devices from slowest to fastest blade speed are 0.25%, 0.82%, and 3.7%, respectively. While these data were collected for devices coated with a 0.6M ink, the same trend of higher short circuit current from faster blade speed was observed at different ink concentrations. In general, more concentrated inks have a slower ideal coating speed than less concentrated inks [C20, C21]. For example, the optimal blade speed for an ink concentration of 0.9M (2:1 ACN: DMSO) was found to be closer to 16 mm / s.

[0541] A key challenge in ambient blade coating of perovskite inks is controlling solvent10046-679W01: 8683 KOR evaporation kinetics during film formation. In the ACN / DMSO system, the binary solvent composition evolves dynamically as the film dries. ACN, with its high vapor pressure (—89 mmHg at 25°C), evaporates much more rapidly than DMSO (~0.6 mmHg), causing the mixture to become progressively DMSO-rich during drying. This preferential evaporation of ACN is captured in the Pxy diagram of Figure 54b, generated using the UNIFAC method in Aspen Plus [C22], which shows the non-ideal vapor-liquid equilibrium of the binary mixture. As ACN is selectively lost to the vapor phase, the viscosity of the remaining solution increases (Figure 54c) [C15], which slows further spreading of the ink within the grooves and ultimately influences the final film morphology.

[0542] To gain control over the evaporation process, an air knife was incorporated into the blade coating setup (Figure 54a) [C17, C19, C23]. The air knife directs a focused stream of gas (N2 used here) across the substrate immediately behind the blade, accelerating solvent removal and quenching film formation at a defined stage of drying. Figure 54d-Figure 54g shows large-area SEM images of devices coated with increasing levels of air knife exposure, with corresponding high-magnification images in Figure 54h-Figure 54k. With insufficient air knife exposure (Figure 54d-Figure 54e, Figure 54h-Figure 54i), excess ink spreads beyond the groove walls, leading to overfilling and perovskite deposition on the ridges between grooves. This cross- contamination of the intended groove geometry introduces shunting pathways and degrades device performance. Conversely, at excessively high air knife exposure (Figure 54g, Figure 54k), the ink is quenched too rapidly, and dendritic formations spread across the top of the grooves.

[0543] The optimal air knife condition (Figure 54f, Figure 54j) balances these competing effects: the perovskite film fills the grooves uniformly without overfilling the groove walls, and no significant formation is observed across grooves. This optimal condition consistently produced the most uniform coating as assessed by SEM, and the most consistent device performance. This optimal condition is detailed in the Experimental Methods.

[0544] Under optimized coating conditions — 16 mm / s blade speed, 0.9M ACN / DMSO (2:1 v / v) ink, and a vertically oriented air knife with 2.5 SCFM — the champion device current density- voltage performance is shown in Figure 55. The cascade of 362 grooves measured under 1 sun simulated illumination yields an open-circuit voltage of 323 V, a short-circuit current density of 28 μA / cm2, a fill factor of 45%, and a power conversion efficiency of 5.7%. The high open-circuit voltage, which exceeds 300 V across the full cascade, arises from the series connection of individual grooves each contributing -890 mV of Voc. The relatively modest PCE reflects the current state of optimization for this novel ink system and ambient coating process; nevertheless, these results represent a significant step forward for scalable, ambient-processed10046-679W01: 8683 KOR flexible PSCs on topographically complex substrates.

[0545] CONCLUSION. Alternative solvents for perovskite precursor inks with lower risks to human health, worker safety, and environmental impact were systematically evaluated. Cyrene, anisole, 2ME-THF, and GVL were found to be insufficient as standalone solvents due to limited solubility of the necessary precursor salts and, in several cases, evidence of iodide oxidation to I2. DMSO, rated as the lowest risk highly coordinating solvent by the CHEM21 solvent guide, was retained as the primary coordinating solvent. Acetonitrile was identified as an effective and recommended co-solvent that enables broad tunability of ink viscosity and vapor pressure without compromising precursor solubility, yielding an optimal formulation of 2:1 ACN: DMSO (v / v) at 0.9M Cso.iFAo.9Pb(Io.95Bro.o5)3.

[0546] Blade coating of this ink onto flexible PET microgroove substrates was optimized with respect to blade speed and air knife-assisted solvent evaporation. A blade speed of 16 mm / s with a vertically oriented air knife providing a flow of 2.5 SCFM of N2 provided the most complete groove filling and continuous perovskite film coverage. SEM characterization confirmed that the combination of these process parameters yields well-defined perovskite deposits confined to the active groove regions. Champion devices demonstrated power conversion efficiencies exceeding 5% with open-circuit voltages surpassing 300 V across a groove cascade under 1 sun simulated illumination, establishing the viability of this approach for ambient, scalable deposition of high-performance flexible perovskite photovoltaics. This work demonstrates that greener solvent systems can be used without sacrificing coating quality or device performance and provides a practical framework for advancing roll-to-roll compatible perovskite PV manufacturing.

[0547] Supplementary Information.

[0548] Figure 56. Photographs showing solubility trials of individual precursor salts in Cyrene, anisole, 2ME-THF, and GVL at 0.6 M, 1.0 M, and 1.2 M concentrations.

[0549] Figure 57. Tauc plot of Cso.iFAo.9Pb(Io.9sBro.o5)3 film on glass.

[0550] Figure 58. (a) Box plots of forward scan PCE values (%) for several samples coated at nDAI concentrations of 0.0, 0.2, 0.5, and 0.8 mg / niL in the precursor ink. A sample that was pre¬ treated (PF) with nDAI is also shown, (b) Plots showing device performance metrics including PCE, Voc, Jsc, and FF as a function of nDAI additive concentration.

[0551] REFERENCES

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[0553] (C2) Wong-Stringer, M. et al. A Flexible Back-Contact Perovskite Solar MicroModule. Energy Environ. Sci. 2019, 12 (6), 1928-1937. https: / / doi.org / 10.1039 / C8EE03517B.10046-679W01: 8683 KOR (C3) Blackburn, D. et al. Back-Contact Perovskite Solar Cell Modules Fabricated via Roll-to-Roll Slot-Die Coating: Scale-Up toward Manufacturing. ACS Appl. Energy Mater. 2025, 8 (4), 2219-2228. https: / / doi.org / 10.1021 / acsaem.4c02734.

[0554] (C4) Jeon, N. J. et al. Solvent Engineering for High-Performance Inorganic-Organic Hybrid Perovskite Solar Cells. Nat. Mater. 2014. https: / / doi.org / 10.1038 / NMAT4014.

[0555] (C5) Nie, W. et al. High-Efficiency Solution-Processed Perovskite Solar Cells with Millimeter-Scale Grains. Science 2015. https: / / doi.org / 10.1126 / SCIENCE.AAA0472.

[0556] (C6) Deng, Y. et al. Scalable Fabrication of Efficient Organolead Trihalide Perovskite Solar Cells with Doctor-Bladed Active Layers. Energy Environ. Sci. 2015. https: / / doi.org / 10.1039 / C4EE03907F.

[0557] (C7) Kim, J. H. et al. Enhanced Environmental Stability of Planar Heterojunction Perovskite Solar Cells Based on Blade-Coating. Adv. Energy Mater. 2015, 5 (4), 1401229. https: / / doi.org / 10.1002 / aenm.201401229.

[0558] (C 8) He, M. et al. Meniscus-Assisted Solution Printing of Large-Grained Perovskite Films for High-Efficiency Solar Cells. Nat. Commun. 2017.

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[0560] (C9) Yang, J. et al. Ink Engineering in Blade-Coating Large-Area Perovskite Solar Cells. Adv. Energy Mater. 2022, 72 (28), 2200975. https: / / doi.org / 10.1002 / aenm.202200975.

[0561] (C IO) Hwang, K. et al. Toward Large Scale Roll-to-Roll Production of Fully Printed Perovskite Solar Cells. Adv. Mater. 2015. https: / / doi.org / 10.1002 / ADMA.201404598.

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[0563] (C12) Hoang, M. T. et al. Towards the Environmentally Friendly Solution Processing of Metal Halide Perovskite Technology. Green Chem. 2021, 23 (15), 5302-5336.

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[0567] (C 15) Grande, M. del C. et al. Density and Viscosity of Anhydrous Mixtures of Dimethylsulfoxide with Acetonitrile in the Range (298.15 to 318.15) K. J. Chem. Eng. Data 2009, 54 (2), 652-658. https: / / doi.org / 10.1021 / je8001909.10046-679W01: 8683 KOR (C 16) Saliba, M. et al. Cesium -Containing Triple Cation Perovskite Solar Cells:

[0568] Improved Stability, Reproducibility and High Efficiency. Energy Environ. Sci. 2016. https: / / doi.org / 10.1039 / C5EE03874J.

[0569] (C17) Deng, Y. et al. Surfactant-Controlled Ink Drying Enables High-Speed Deposition of Perovskite Films for Efficient Photovoltaic Modules. Nat. Energy 2018, 3 (7), 560-566. https: / / doi.org / 10.1038 / s41560-018-0153-9.

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[0579] Example 8 - Groove Fill Drives Solvent Based Performance Differences in Microgroove Array Photovoltaics

[0580] Abstract. Photovoltaic devices (PVs) were fabricated using an innovative back contact architecture on plastic substrates that features a cascade of parallel microgrooves, each spanning 1.5 pm in width. This is a promising way to produce mechanically flexible PV modules using roll-to-roll manufacturing processes in which the electron and hole transport layers are added to opposing groove sidewalls by shadow deposition and the light absorbing material is deposited within the grooves by solvent or spray-based methods. Metal halide perovskites, such as methyl ammonium lead iodide ((CH3NH3)PbI3, MAPI), are particularly suitable light-absorber materials for this architecture because they can be deposited at low temperature from solvents and achieve high device efficiencies. However, MAPI and other perovskites are generally deposited from relatively toxic solvents, like dimethyl formamide (DMF). DMF is effective since it is a10046-679W01: 8683 KOR coordinating solvent with low volatility, but in many jurisdictions, DMF and other similar solvents cannot be used for large-scale manufacturing. Currently a number of green solvent alternatives exist for traditionally coated flat cells. However, the microgroove architecture as well as the plastic substrate adds additional coating dynamics that alter device performance. This creates a challenge of finding a “greener” solvent that enables high performance, while also providing for effective groove filling. Herein, it is found that films of methylammonium lead iodide perovskite made with different solvents form drastically different morphologies on a microgroove substrate than a flat one. Because of this common green solvent alternatives are not viable for use in depositing active layers. In this work it is identifies that the performance of microgroove devices suffer performance losses in open circuit voltages from solvent dependent groove fill (Figure 59).

[0581] Introduction. Perovskites are a class of materials with the general formula ABX3 where A and B are cations and X represents an anion. Lead halide perovskites, where the B cation is Pb and X is a halogen anion, are of interest in the fields of optics due to their long charge carrier lifetimes [DI], high absorbance coefficients [D2], tunable bandgaps [D3], and the high tolerance of their optical and electronic properties towards structural defects [D4-D6], Their competitive solubility, due to them being ionic, allows for them to be solution processable, which means that they can be utilized in flexible roll-to-roll photovoltaics [D7, D8], This coupled with tunable photoluminescence emissions across the entire visible spectrum [D9] makes them viable candidates for next generation photovoltaics (PV). Perovskite PV devices were first published in 2009 with a reported power conversion efficiency (PCE) of 3.8% [DIO], Since then, due to its inherent tunability and favorable optoelectronic properties, perovskite PVs have reached power conversion efficiencies up to 26.1% [Dll], enough to rival single crystal silicon cells. This is extremely promising as further research could push perovskite photovoltaic devices into wide- scale production and proliferation, combating harmful climate change and increasing global energy access.

[0582] A route towards roll to roll production of flexible photovoltaics can be achieved through the utilization of microgroove photovoltaics [D12-D14], The flexible back contact architecture of the microgroove devices lead to the ability to manufacture an array of photovoltaics a roll-to-roll process.

[0583] It is known that the perovskite composition as well as morphology effect the relevant optoelectronic properties (mobility, diffusion length, lifetime, optical bandgap) [D15, D16, D17], The morphology of perovskite films is also highly dependent on their deposition, as they undergo deposition dependent crystallization. In addition, this microgroove architecture adds10046-679W01: 8683 KOR additional morphologically based performance effects. In addition, the traps and defects associated with the introduction of more grain boundaries [D15] the microgroove devices can suffer performance losses from overfilling and underfilling of the grooves. Herein common nonvolatile coordinating solvents and volatile coordinating solvents are explored to assess their viability for high throughput deposition on flexible back contact microgroove devices.

[0584] Results and Discussion

[0585] Deposition Dependent Photovoltaic Performance. The morphology of solution processable perovskites is highly dependent on the solvent used [D18J. Solvent engineering methods have been used to improve the film quality and device performance of planer photovoltaic cells [D 191. By controlling the intermediate complexes present as well as the evaporation rates of solvents smooth uniform films of perovskites can be deposited onto mesoporous electron transport layers [DI 8], The use of flexible back contact microgroove architecture was found to introduce additional parameters that affect device performance, such as groove fill and the presence of gapping between the active layer and the transport layers. The top-down scanning electron microscopy images presented in Figure 61 also show the drastic differences in crystal grain growth on flat substrates opposed to microgrooves. In addition to this it can be seen that Methylammonium lead iodide active layers perform better in microgroove devices when deposited in Dimethyl Formamide as the solvent (Figure 60a). Upon separating the PCE into short circuit current and open circuit voltage, it shows that the performance differences come primarily from open circuit voltage losses (Figure 60b).

[0586] The performance differences to transient and steady state photoluminescence data of films made with different solvents shows that films made with the MA / Acetonitrile solvent display drastically longer PL lifetimes than those made with DMF and GVL. This is consistent with reports of high quality film formation using this solvent [D20J. The short circuit currents of devices made with these solvent systems (Figure 60b) follow the same trends as the steady state and transient PL measurements of the MA / Acetonitrile having the highest optical performance and the GVL having the lowest.

[0587] Despite the short circuit currents aligning well with optical data, the performance does not align with the optical data. Rather, the performance differences primarily follow differences in open circuit voltage. Losses in open circuit voltage are often the result of series resistance that results from poor electro n / hole extraction at the transport layer interfaces [D21 ]. Due to the back contact architecture of the microgroove devices the solvent must coat the sides of the microgrooves completely without sticking to the top of the microgrooves to maintain good contact with the transport layers. When comparing the differences in film formation between10046-679W01: 8683 KOR microgrooves and flat cells it can be seen that the perovskite forms differently on the microgrooves. In Figure 62a and Figure 62d the MAPI deposited from DMF forms larger crystal grains within the microgrooves compared to flat silicon. While the films made with

[0588] MA / Acetonitrile appear to form similarly on both the microgroove substrates and the silicon (Figure 62b, Figure 62e).

[0589] X-Ray Diffraction of MAPI films display that the films made with GVL have a small amount of left over lead iodide. This is likely a portion of the performance losses seen with this solvent. In addition to this films made with this solvent have large areas of gapping (Figure 62f). In contrast, when used to deposit perovskite films on a microgroove substrate less severe gapping can be observed (Figure 62c).

[0590] Conclusions. Perovskite photovoltaic active layers fabricated on microgroove substrates display drastically different morphologies than when deposited on flat substrates. Due to this, photovoltaic performance of microgroove devices does not necessarily align with the optical activity of the active layer. It is also seen that the solvent properties greatly affect the film morphology in ways that do not exist in flat cells (gapping, and overfilling). Because of this more work needs to be done to identify ideal solvent systems for optimal groove filling. As a result, the search for greener solvent alternatives for microgroove photovoltaics will be more challenging than that of traditional flat cells. More work must be done to identify ideal solvent systems that can not only optimize groove fill but also allow for scalability in roll to roll manufacturing.

[0591] Experimental Methods

[0592] Materials. Lead (II) Iodide (Pbh, 99.999% trace metal basis) and MA / Acetonitrile C. A.

[0593] 9%’ were purchased from Tokyo Chemical Industries. Dimethyl Formamide (DMF, 99.8%, anhydrous), Dimethyl Sulfoxide (DMSO, 99.9%, anhydrous), and Gamma- Valero Acetone (BioRenewable, anhydrous, DMF and NMP substitute, >99%) were purchased from Sigma Aldrich. Methyl Ammonium Iodide was purchased from Great Cell Solar. All materials were used as received without further purification. Glass slides (Cardinal Health, plain microscope).

[0594] Substrate Fabrication. Polyethylene terephthalate (PET) substrates were microembossed roll-to-roll using a continuous UV casting process creating individual units / panels (100 mm X 100 mm) of micro-groove cascades. These rolls of embossed material were then coated roll-to-roll via e-beam and thermal evaporation. Glancing angle deposition was utilized to deposit the conductive, HTL and ETL layers on either side of the microgroove wall.

[0595] Supplementary Information.

[0596] Figure 63. X-Ray Diffraction of MAPbI3 films deposited from different solvents.10046-679W01: 8683 KOR Figure 64. b) contact angle of DMF on electron transport layer c) contact angle of DMF on hole transport layer d) cross sectional SEM of methylamine / acetonitrile based perovskite films e) contact angle of methylamine / acetonitrile on electron transport layer f) contact angle of methylamine acetonitrile on hole transport layer h) contact angle of γ-valerolactone on electron transport layer i) contact angle of γ-valerolactone on hole transport layer.

[0597] Figure 65. a,b) contact angle of DMF on electron transport layer, hole transport layer c.d) contact angle of 9: 1 v:v solution of DMF: DMSO on electron transport layer, hole transport layer e,f) contact angle of a 1: 1 v:v solution of DMF: DMSO on electron transport layer, hole transport layer g,h) contact angle of a 1:9 v:v solution of DMF: DMSO on electron transport layer, hole transport layer i,j) contact angle of DMSO on electron transport layer, hole transport layer.

[0598] References

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[0612] (D13) Wong-Stringer, M. et al. A Flexible Back-Contact Perovskite Solar Micro¬ Module. Energy Environ. Sci. 2019, 12 (6), 1928-1937. https: / / doi.org / 10.1039 / C8EE03517B.

[0613] (D14) Blackburn, D. et al. Back-Contact Perovskite Solar Cell Modules Fabricated via Roll-to-Roll Slot-Die Coating: Scale-Up toward Manufacturing. ACS Appl. Energy Mater. 2025, 8 (4), 2219-2228. https: / / doi.org / 10.1021 / acsaem.4c02734.

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[0615] (D16) Rolston, N. et al. Effect of Cation Composition on the Mechanical Stability of Perovskite Solar Cells. Advanced Energy Materials 2018, 8 (9), 1702116.

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[0623] (D21) Daboczi, M. et al. Origin of Open-Circuit Voltage Losses in Perovskite Solar Cells Investigated by Surface Photovoltage Measurement. ACS Appl. Mater. Interfaces 2019, 11 (50), 46808-46817. https: / / doi.org / 10.1021 / acsami.9b16394.

[0624] Example 9

[0625] Inclusion of DAI in the perovskite ink resulted differences in surface hydrophobicity (Figure 37), crystal structure (Figure 33), optical properties (Figure 34), and thermal stability (Figure 46) of the perovskite film.

[0626] Inclusion of DAI in perovskite inks improves stability from heat and moisture.

[0627] Figure 66. Aging (50°C and 50 RH%) of Cso.iFAo.9Pb(Io.95Bro.o5)3 films with 2 mg / mL DAI or without.

[0628] Figure 67. Ratio of perovskite peak vs lead peak formation during aging (50°C and 50 RH%) of Cso.iFAo.9Pb(Io.95Bro.o5)3 films with 2 mg / mL DAI or without.

[0629] EXEMPLARY ASPECTS

[0630] In view of the described compositions, devices, systems, and methods, herein below are described certain more particularly described aspects of the inventions. The particularly recited aspects should not, however, be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein or that the “particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.

[0631] Example 1: A double cation perovskite comprising: CsxFA1-xPb(I1-yBry)3, where FA is formamidinium; x is from greater than 0 to less than 1; and y is from greater than 0 to less than 1.

[0632] Example 2: The perovskite of any example herein, particularly example 1, wherein the double cation perovskite is substantially free of methyl ammonium.

[0633] Example 3: The perovskite of any example herein, particularly example 1 or example 2, wherein the double cation perovskite consists essentially of CsxFA1-xPb(I1-yBry)3.

[0634] Example 4: The perovskite of any example herein, particularly examples 1-3, wherein the double cation perovskite consists of CsxFA1-xPb(I1-yBry)3.

[0635] Example 5: The perovskite of any example herein, particularly examples 1-4, wherein x is from 0.05 to 0.15.10046-679W01: 8683 KOR Example 6: The perovskite of any example herein, particularly examples 1-5, wherein x is 0.05, 0.07, 0.1, or 0.15.

[0636] Example 7: The perovskite of any example herein, particularly examples 1-6, wherein x is 0.1.

[0637] Example 8: The perovskite of any example herein, particularly examples 1-7, wherein y is 0.05.

[0638] Example 9: The perovskite of any example herein, particularly examples 1-8, wherein x is from 0.05 to 0.15 and y is 0.05.

[0639] Example 10: The perovskite of any example herein, particularly examples 1-9, wherein x is 0.05, 0.07, 0.1, or 0.15 and wherein y is 0.05.

[0640] Example 11: The perovskite of any example herein, particularly examples 1-10, wherein the double cation perovskite comprises Cso.iFAo.9Pb(Io.95Bro.os)3.

[0641] Example 12: The perovskite of any example herein, particularly examples 1-11, wherein the double cation perovskite comprises Cso.iFAo.9Pb(Io.9sBro.o5)3 and is substantially free of methylammonium.

[0642] Example 13: The perovskite of any example herein, particularly examples 1-12, wherein the double cation perovskite consists essentially of Cso.iFAo.9Pb(Io95Bro.o5)3.

[0643] Example 14: The perovskite of any example herein, particularly examples 1-13, wherein the double cation perovskite consists of Cso.iFAo. Pb(Io. 5Bro.o5)3.

[0644] Example 15: An ink comprising the perovskite of any example herein, particularly examples 1-14 and a solvent.

[0645] Example 16: The ink of any example herein, particularly example 15, wherein the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0646] Example 17: The ink of any example herein, particularly example 15 or example 16, wherein the solvent comprises the solvent system of any example herein, particularly examples 31-39.

[0647] Example 18: The ink of any example herein, particularly examples 1 -17, wherein the ink further comprises an additive.

[0648] Example 19: The ink of any example herein, particularly example 18, wherein the additive comprises dodecylammonium iodide (DAI).

[0649] Example 20: The ink of any example herein, particularly example 18 or example 19, wherein the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / ml.. such as 2 mg / ml...10046-679W01: 8683 KOR Example 21: The ink of any example herein, particularly examples 18-20, wherein the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0650] Example 22: A perovskite ink comprising a perovskite, a solvent, and an additive, wherein the additive comprises dodecylammonium iodide (DAI).

[0651] Example 23: The ink of any example herein, particularly example 22, wherein the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0652] Example 24: The ink of any example herein, particularly example 22 or example 23, wherein the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0653] Example 25: The ink of any example herein, particularly examples 22-24, wherein the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0654] Example 26: The ink of any example herein, particularly examples 22-25, wherein the perovskite comprises a double cation perovskite.

[0655] Example 27: The ink of any example herein, particularly example 26, wherein the cations comprise FA and Cs.

[0656] Example 28: The ink of any example herein, particularly examples 22-27, wherein the perovskite is substantially free of methylammonium.

[0657] Example 29: The ink of any example herein, particularly examples 22-28, wherein the perovskite is a multi-halide perovskite.

[0658] Example 30: The ink of any example herein, particularly example 28, wherein the halides comprise I and Br.

[0659] Example 31: The ink of any example herein, particularly examples 22-30, wherein the perovskite is the perovskite of any example herein, particularly examples 1-14.10046-679W01: 8683 KOR Example 32: The ink of any example herein, particularly examples 22-31, wherein the solvent comprises the solvent system of any example herein, particularly examples 33-41.

[0660] Example 33: A solvent system for preparing perovskite films from perovskite inks, the solvent system comprising acetonitrile (ACN) and dimethyl sulfoxide (DMSO).

[0661] Example 34: The solvent system of any example herein, particularly example 33, wherein the DMSO is a coordinating solvent to dissolve the perovskite and acetonitrile is a diluting solvent.

[0662] Example 35: The solvent system of any example herein, particularly example 33 or example 34, wherein the solvent system is substantially free of methylamine.

[0663] Example 36: The solvent system of any example herein, particularly examples 33-35, wherein the solvent system comprises ACN in an amount of from greater than 0 to less than 100 % (v / v), based on the total volume of ACN and DMSO.

[0664] Example 37: The solvent system of any example herein, particularly examples 33-36, wherein the solvent system comprises ACN in an amount of from 50 to 83.3% (v / v), such as from 50 to 75% (v / v), such as 66% (v / v), based on the total volume of ACN and DMSO.

[0665] Example 38: The solvent system of any example herein, particularly examples 33-37, wherein the solvent system comprises ACN and DMSO in a volume ratio (ACN: DMSO) of from 10:1 to 1:10

[0666] Example 39: The solvent system of any example herein, particularly examples 33-38, wherein the solvent system comprises ACN and DMSO in a volume ratio (ACN: DMSO) of from 5: 1 to 1:1, such as from 3:1 to 1:1, such as 2: 1.

[0667] Example 40: The solvent system of any example herein, particularly examples 33-39, wherein the solvent system consists essentially of acetonitrile and dimethyl sulfoxide (DMSO).

[0668] Example 41: The solvent system of any example herein, particularly examples 33-40, wherein the solvent system consists of acetonitrile and dimethyl sulfoxide (DMSO).

[0669] Example 42: An ink comprising a perovskite and the solvent system of any example herein, particularly examples 33-41.

[0670] Example 43: The ink of any example herein, particularly example 42, wherein the ink includes the perovskite at a concentration of from 0.1 to 3 M such as from 0.5 to 1.5 M, such as 0.9 M.

[0671] Example 44: The ink of any example herein, particularly example 42 or example 43, wherein the perovskite comprises a double cation perovskite.

[0672] Example 45: The ink of any example herein, particularly example 44, wherein the cations comprise FA and Cs.10046-679W01: 8683 KOR Example 46: The ink of any example herein, particularly examples 42-45, wherein the perovskite is substantially free of methylammonium.

[0673] Example 47: The ink of any example herein, particularly examples 42-46, wherein the perovskite is a multi-halide perovskite.

[0674] Example 48: The ink of any example herein, particularly example 47, wherein the halides comprise I and Br.

[0675] Example 49: The ink of any example herein, particularly examples 42-48, wherein the perovskite is the perovskite of any example herein, particularly examples 1-14.

[0676] Example 50: The ink of any example herein, particularly examples 42-49, wherein the ink further comprises an additive.

[0677] Example 51: The ink of any example herein, particularly example 50, wherein the additive comprises dodecylammonium iodide (DAI).

[0678] Example 52: The ink of any example herein, particularly example 50 or example 51, wherein the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0679] Example 53: The ink of any example herein, particularly examples 50-52, wherein the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0680] Example 54: The ink of any example herein, particularly examples 42-53, wherein the ink is ambient processable.

[0681] Example 55: The ink of any example herein, particularly examples 42-54, wherein the ink is less toxic than a similar ink comprising conventional perovskite ink processing solvents.

[0682] Example 56: The ink of any example herein, particularly examples 42-55, wherein the ink is greener than a similar ink comprising conventional perovskite ink processing solvents.

[0683] Example 57: The ink of any example herein, particularly examples 42-56, wherein the ink is compatible with blade coating, such as air knife-assisted ambient blade coating.

[0684] Example 58: The ink of any example herein, particularly examples 42-57, wherein the ink is compatible with roll-to-roll processing.

[0685] Example 59: The ink of any example herein, particularly examples 42-58, wherein the ink is compatible with flexible substrates.10046-679W01: 8683 KOR Example 60: The ink of any example herein, particularly examples 42-59, wherein the ink is compatible with flexible microgroove substrates, such as those described in Blackburn et al. ACS Applied Energy Materials, 2025, 8(4), 2219-2228; Pemik et al. 2016, ACS Energy Letters, 1(5), 1021-1027; Wong-Stringer et al. 2019, Energy and Environmental Science, 2019, 12(6), 1928–1937; WO 2014 / 118545 and / or WO 2012 / 175902.

[0686] Example 61: The ink of any example herein, particularly examples 42-60, wherein the ink is capable of preparing a perovskite film on a substrate, such as the flexible microgroove substrate, that is substantially more uniform relative to a film prepared using conventional perovskite ink processing solvents.

[0687] Example 62: A method of making a perovskite film, comprising depositing a perovskite ink on a substrate, wherein the perovskite ink comprises a perovskite and a solvent, wherein the perovskite is the perovskite of any example herein, particularly examples 1-14, the solvent is the solvent system of any example herein, particularly examples 33-41, the perovskite ink is that of any example herein, particularly examples 15-32 or 42-61, or a combination thereof.

[0688] Example 63: The method of any example herein, particularly example 62, wherein the perovskite of any example herein, particularly examples 1-14.

[0689] Example 64: The method of any example herein, particularly example 62 or example 63, wherein the solvent is the solvent system of any example herein, particularly examples 33-41.

[0690] Example 65: The method of any example herein, particularly examples 62-64, wherein the perovskite of any example herein, particularly examples 1-14 and wherein the solvent is the solvent system of any example herein, particularly examples 33-41.

[0691] Example 66: The method of any example herein, particularly examples 62-65, wherein the perovskite ink is that of any example herein, particularly examples 15-32 or 42-61.

[0692] Example 67: The method of any example herein, particularly examples 62-66, wherein the perovskite ink further comprises an additive.

[0693] Example 68: The method of any example herein, particularly example 67, wherein the additive comprises dodecylammonium iodide (DAI).

[0694] Example 69: The method of any example herein, particularly example 67 or example 68, wherein the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0695] Example 70: The method of any example herein, particularly examples 67-69, wherein the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal10046-679W01: 8683 KOR structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0696] Example 71: The method of any example herein, particularly examples 62-70, wherein the method further comprises pre-treating the substrate before depositing the perovskite ink.

[0697] Example 72: The method of any example herein, particularly example 71, wherein pre¬ treating comprises depositing a pre-treatment compound onto the substrate before depositing the perovskite ink.

[0698] Example 73: The method of any example herein, particularly example 71 or example 72, wherein the pre-treatment compound modifies the surface energy of the substrate, for example by optimizing the surface Fermi level, passivating at least a portion of the surface to reduce defect density, improving wettability, or a combination thereof.

[0699] Example 74: The method of any example herein, particularly examples 71-73, wherein the pre-treatment compound comprises phenethylammonium iodide (PEAI).

[0700] Example 75: A method of making a perovskite film, comprising pre-treating a substrate with a pretreatment compound comprising phenethylammonium iodide (PEAI), and subsequently depositing a perovskite ink on the pre -treated substrate, wherein the perovskite ink comprises a perovskite and a solvent.

[0701] Example 76: The method of any example herein, particularly example 75, wherein pre-treating comprises depositing the pre-treatment compound onto the substrate before depositing the perovskite ink.

[0702] Example 77: The method of any example herein, particularly example 75 or example 76, wherein the pre-treatment compound modifies the surface energy of the substrate, for example by optimizing the surface Fermi level, passivating at least a portion of the surface to reduce defect density, improving wettability, or a combination thereof.

[0703] Example 78: The method of any example herein, particularly examples 75-77, wherein the perovskite comprises a double cation perovskite.

[0704] Example 79: The method of any example herein, particularly example 78, wherein the cations comprise FA and Cs.

[0705] Example 80: The method of any example herein, particularly examples 75-79, wherein the perovskite is substantially free of methylammonium.

[0706] Example 81: The method of any example herein, particularly examples 75-80, wherein the perovskite is a multi-halide perovskite.

[0707] Example 82: The method of any example herein, particularly example 81, wherein the10046-679W01: 8683 KOR halides comprise I and Br.

[0708] Example 83: The method of any example herein, particularly examples 75-82, wherein the perovskite of any example herein, particularly examples 1-14.

[0709] Example 84: The method of any example herein, particularly examples 75-83, wherein the solvent is the solvent system of any example herein, particularly examples 33-41.

[0710] Example 85: The method of any example herein, particularly examples 75-84, wherein the perovskite of any example herein, particularly examples 1-14 and wherein the solvent is the solvent system of any example herein, particularly examples 33-41.

[0711] Example 86: The method of any example herein, particularly examples 75-85, wherein the perovskite ink is that of any example herein, particularly examples 15-32 or 42-61.

[0712] Example 87: The method of any example herein, particularly examples 75-86, wherein the perovskite ink further comprises an additive.

[0713] Example 88: The method of any example herein, particularly example 87, wherein the additive comprises dodecylammonium iodide (DAI).

[0714] Example 89: The method of any example herein, particularly example 87 or example 88, wherein the perovskite ink includes the additive at a concentration of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

[0715] Example 90: The method of any example herein, particularly examples 87-89, wherein the additive can improve grain size and / or crystallinity of a perovskite film made from the perovskite ink, which thereby can improve power conversion efficiency of a photovoltaic device comprising said perovskite film; the additive can affect the surface hydrophobicity, crystal structure, optical properties, and / or thermal stability of a perovskite film prepared from said ink; the additive can improve the stability of a perovskite film prepared from said ink, for example to heat and / or moisture; or a combination thereof.

[0716] Example 91: The method of any example herein, particularly examples 62-90, wherein the substrate is rigid.

[0717] Example 92: The method of any example herein, particularly examples 62-91, wherein the substrate comprises glass and / or silicon.

[0718] Example 93: The method of any example herein, particularly examples 62-92, wherein the substrate is flexible.

[0719] Example 94: The method of any example herein, particularly examples 62-93, wherein the substrate is flexible and comprises a polymer, such as an acrylic polymer, polyethylene terephthalate, or a combination thereof.

[0720] Example 95: The method of any example herein, particularly examples 62-94, wherein10046-679W01: 8683 KOR the substrate is substantially flat.

[0721] Example 96: The method of any example herein, particularly examples 62-95, wherein the substrate is grooved, such as with microgrooves.

[0722] Example 97: The method of any example herein, particularly examples 62-96, wherein the substrate is a flexible microgroove substrate, such as those described in Blackburn et al. ACS Applied Energy Materials, 2025, 8(4), 2219-2228; Pemik et al. 2016, ACS Energy Letters, 1(5), 1021-1027; Wong-Stringer et al. 2019, Energy and Environmental Science, 2019, 12(6), 1928–1937; WO 2014 / 118545 and / or WO 2012 / 175902.

[0723] Example 98: The method of any example herein, particularly examples 62-97, wherein depositing comprises spin coating, blade coating, slot-die coating, gravure coating, chemical bath / vapor deposition, roll-to-roll processing, spray coating, or a combination thereof.

[0724] Example 99: The method of any example herein, particularly examples 62-98, wherein depositing comprises blade coating, slot-die coating, gravure coating, chemical bath / vapor deposition, roll-to-roll processing, or a combination thereof.

[0725] Example 100: The method of any example herein, particularly examples 62-99, wherein depositing comprises blade coating, such as air knife-assisted ambient blade coating.

[0726] Example 101: The method of any example herein, particularly examples 62-100, wherein depositing comprises roll-to-roll processing.

[0727] Example 102: The method of any example herein, particularly examples 62-101, wherein the method is performed at ambient conditions.

[0728] Example 103: A perovskite film made by the methods of any example herein, particularly examples 62-102.

[0729] Example 104: The film of any example herein, particularly example 103, wherein the film comprises the perovskite as a-phase.

[0730] Example 105: A method of use of the perovskite film made by the methods of any example herein, particularly examples 62-102.

[0731] Example 106: The method of any example herein, particularly example 105, wherein the method comprises using the film in a photovoltaic device, such as a solar cell.

[0732] Example 107: The method of any example herein, particularly example 105 or example 106, wherein the method comprises using the film for sensing, for catalysis, in a battery, in a LED, or a combination thereof.

[0733] Example 108: An article of manufacture comprising the perovskite film made by the methods of any example herein, particularly examples 62-102.

[0734] Example 109: The article of any example herein, particularly example 108, wherein the10046-679W01: 8683 KOR article is a photovoltaic device, such as a solar cell.

[0735] Example 110: The article of any example herein, particularly example 108 or example 109, wherein the article is a battery, LED, or a combination thereof.

[0736] Example: A photovoltaic device comprising the perovskite film made by the methods of any example herein, particularly examples 62-102.

[0737] Example: The photovoltaic device of any example herein, particularly example 111, wherein the photovoltaic device is a solar cell.

[0738] Other advantages which are obvious and which are inherent to the invention will be evident to one skilled in the art. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

[0739] The compositions, systems, and methods of the appended claims are not limited in scope by the specific compositions, system, and methods described herein, which are intended as illustrations of a few aspects of the claims and any methods that are functionally equivalent are intended to fall within the scope of the claims. Various modifications of the compositions, systems, and methods in addition to those shown and described herein are intended to fall within the scope of the appended claims. Further, while only certain representative composition elements, system elements, and method steps disclosed herein are specifically described, other combinations of the composition elements, system elements, and method steps also are intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents may be explicitly mentioned herein or less, however, other combinations of steps, elements, components, and constituents are included, even though not explicitly stated.

Claims

10046-679W01: 8683 KOR CLAIMSWhat is claimed:

1. A double cation perovskite comprising:CsxFAi.xPb(Ii.yBry)3whereFA is fonuamidinium;x is from greater than 0 to less than 1; andy is from greater than 0 to less than 1.

2. The perovskite of claim 1, wherein x is from 0.05 to 0.15, such as wherein x is 0.

1.

3. The perovskite of any one of claims 1-2, wherein the double cation perovskite comprises Cso.iFAo.9Pb(Io.95Bro.o5)3.

4. A solvent system for preparing perovskite films from perovskite inks, the solvent system comprising acetonitrile (ACN) and dimethyl sulfoxide (DMSO).

5. The solvent system of claim 4, wherein the solvent system comprises ACN in an amount of from greater than 0 to less than 100 % (v / v),, such as from 50 to 83.3% (v / v), such as from 50 to 75% (v / v), such as 66% (v / v), based on the total volume of ACN and DMSO.

6. The solvent system of any one of claims 4-5, wherein the solvent system comprises ACN and DMSO in a volume ratio (ACN: DMSO) of from 10:1 to 1:10, such as from 5:1 to 1:1, such as from 3:1 to 1:1, such as 2:1.

7. An ink comprising the perovskite of any one of claims 1-3 and a solvent.

8. The ink of claim 7, wherein the solvent comprises the solvent system of any one of claims 4-6.

9. An ink comprising a perovskite and the solvent system of any one of claims 4-6.

10. The ink of claim 9, wherein the perovskite is the perovskite of any one of claims 1-3.

11. The ink of any one of claims 7-10, wherein the ink further comprises an additive, wherein the additive comprises dodecylammonium iodide (DAI).

12. The ink of claim 11, wherein the perovskite ink includes the additive at a concentration10046-679W01: 8683 KOR of from greater than 0 to 10 mg / mL, such as 2 mg / mL.

13. A method of making a perovskite film, comprising depositing a perovskite ink on a substrate, wherein the perovskite ink comprises a perovskite and a solvent, wherein the perovskite is the perovskite of any one of claims 1-3, the solvent is the solvent system of any one of claims 4-6, the perovskite ink is that of any one of claims 7-12, or a combination thereof.

14. The method of claim 13, wherein the method further comprises pre-treating the substrate before depositing the perovskite ink.

15. The method of claim 14, wherein pre-treating comprises depositing a pre-treatment compound onto the substrate before depositing the perovskite ink, wherein the pre-treatment compound comprises phenethylammonium iodide (PEAI).

16. The method of any one of claims 13-15, wherein the substrate is flexible.

17. The method of any one of claims 13-16, wherein the substrate is grooved, such as with microgrooves.

18. The method of any one of claims 13-17, wherein the method is performed at ambient conditions.

19. A method of use of the perovskite film made by the methods of any one of claims 13-18, wherein the method comprises using the film in a photovoltaic device, such as a solar cell.

20. A photovoltaic device comprising the perovskite film made by the methods of any one of claims 13-18.

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