RECYCLING LEAD AND TRANSPARENT CONDUCTORS FROM PEROVSKITE SOLAR MODULES CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to United States Provisional Application No.63/234,992, filed August 19, 2021, the contents of which are incorporated by reference herein in their entirety for all purposes. FIELD OF THE INVENTION The presently disclosed subject matter relates generally to methods for recycling lead from lead-containing materials. In certain embodiments, the lead-containing material is a perovskite material harvested from a perovskite solar module. GOVERNMENT SUPPORT This invention was made with government support under Grant Number DE-EE0008749 awarded by the Department of Energy. The government has certain rights in the invention. BACKGROUND Power conversion efficiencies (PCEs) have exceeded 25% for single junction perovskite solar cells (PSCs) and 29% for perovskite/silicon tandem solar cells (NREL best research-cell efficiency chart). Large area perovskite modules have successfully been fabricated with scalable coating processes, producing efficiencies comparable to those of silicon modules. The stability of perovskite solar cells has also improved significantly, passing most industrial standard tests (Extance, A. Nature 570, 429-432, (2019); Cheacharoen, R. et al. Sustainable Energy & Fuels 2, 2398-2406, (2018)). All of these developments demonstrate the potential for perovskite photovoltaics as the next-generation low-cost solar technology. Worldwide, perovskite solar cells, including both single junction solar cells, as well as tandem solar cells, are being pursued commercially. Nevertheless, an outstanding concern for the widespread adoption of perovskite photovoltaic technology is the toxicity of lead (Pb) in lead halide perovskite light absorbers (Rong, Y. et al. Science 361, eaat8235, (2018); Rajagopal, A., et al. Adv. Mater.30, 1800455, (2018)). Although there have been extensive efforts to replace lead in PSCs, lead-free PSCs commonly suffer from either poorer stability, such as the tin-based PSCs, or lower PCEs, such as those exemplified by double-perovskite based solar cells (Ke, W. & Kanatzidis, M. G. Nat. Commun.10, 965, (2019); Kamat, P. V., et al. ACS Energy Lett.2, 904-905, (2017)). As such, lead helps promote perovskite PSCs with both high efficiencies and good operational stability (Yang, S. et al. Science 365, 473-478, (2019); Wang, L. et al. Science 363, 265-270, (2019); Wang, Y. et al. Science 365, 687-691, (2019); Tan, H. et al. Science 355, 722-726, (2017)). Several methods have been investigated with the aim of trapping lead in perovskite solar cells to prevent the lead from leaving the cell under extreme weather conditions. See, e.g., Li, X. et al. Nature, 578, 555-558, 2 (2020); Chen, S. et al. Nat. Energy, 5, 1003-1011, (2020); and Chen, S. et al. Nat. Sustain., (2021). However, what is still needed in the art is a lead waste management system for end-of-life perovskite solar modules to properly dispose of and recycle the lead-based perovskite solar modules. The subject matter described herein addresses this unmet need. BRIEF SUMMARY In one aspect, the presently disclosed subject matter is directed to a method for preparing a lead halide, comprising: contacting a lead-containing material with an organic solvent to form a first solution; contacting said first solution with a weakly acidic cation exchange material, wherein said weakly acidic cation (WAC) exchange material adsorbs Pb ²⁺ from said first solution to form a weakly acidic cation exchange material comprising Pb ²⁺ ; contacting said weakly acidic cation exchange material comprising Pb ²⁺ with an acid to produce a solution comprising a soluble lead compound; contacting said solution comprising a soluble lead compound with an alkali metal halide solution to prepare a second solution; and precipitating said lead halide. In another aspect, the presently disclosed subject matter is directed to a method for recovering lead from lead waste, comprising: contacting said lead waste with an organic solvent to form a first solution; contacting said first solution with a weakly acidic cation exchange material, wherein said weakly acidic cation exchange material adsorbs Pb ²⁺ from said first solution to form a weakly acidic cation exchange material comprising Pb ²⁺ ; contacting said weakly acidic cation exchange material comprising Pb ²⁺ with an acid to produce a solution comprising a soluble lead compound; and contacting said solution comprising a soluble lead compound with an alkali metal halide solution to prepare a second solution; and precipitating a lead halide. These and other aspects are described herein. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a roadmap for recycling perovskite solar modules.1) Encapsulated perovskite solar modules were delaminated and the lead halide perovskite was dissolved in dimethylformamide (DMF).2) Lead ions in the DMF were removed by a carboxylic acid cation exchange resin.3) The adsorbed lead ions on the resin were released to aqueous solution by a resin regeneration process via HNO ₃ .4) Precipitation of PbI ₂ by pouring NaI into a Pb(NO ₃ ) ₂ - containing solution.5) Module refabrication based on recycled materials. Figure 2 shows a thermal delamination process for an encapsulated perovskite solar module. (a) Schematic illustration for delamination at the electron transport layer and metal electrode interface. (b) Photo of a perovskite solar module, delaminated module at ITO coated glass (ITO/glass) side and back cover glass side, and recycled ITO/glass and cover glass after cleaning. The front glass size is 8.5 cm ×6.5 cm. (c) A plot showing the change in the sheet resistance for ITO-coated glass substrate after thermal annealing at 250 °C for 1 hour under ambient atmosphere. Figure 3 shows data plots and images obtained through lead recycling experiments. (a) A plot of the lead removal ratio of different concentrations of PbI ₂ solution in DMF after stirring with 1 g cation exchange resins for 20 hours. (b) A plot of the lead release ratio of 1g cation exchange resins under different concentrations of HNO3 for 30 min. (c) A plot of the adsorption kinetics and (d) second-order kinetic fit for lead adsorption onto WAC-gel resin at different initial Pb concentrations. (e) A plot of the lead adsorption for 10 mL of 8300 ppm lead in DMF by WAC-gel single-treatment and three-treatments. Single-treatment was carried out with 1 g WAC-gel for 20 hours. The three-treatments were carried out with 1 g WAC-gel for 1 hour; then, 1g fresh resin was transferred into the PbI ₂ solution for the second and third treatments. (f) A plot of the lead release ratio from WAC-gel resin under 1M HNO3 under different periods of time. (g) A photo of PbI2 precipitate, which was generated following contacting a 1.5 M NaI solution with a Pb(NO ₃ ) ₂ containing solution. The Pb(NO ₃ ) ₂ containing solution was obtained through regeneration of the lead adsorbed WAC-gel resin. (h) A bar graph of the lead recycling ratio of 10 mL 40 mM PbI2 in DMF by WAC-gel three-treatments, lead release by HNO3 solution for 30 min, and lead conversion by reaction with NaI solution. Figure 4 shows the results of comparative lead recycling experiments for PbI2 and Cs0.1FA0.9PbI3, as well as the PCEs of modules generated from recycled PbI2 or recycled ITO. (a) A plot of the lead adsorption kinetics for 10 mL of 40 mM PbI ₂ and 40 mM Cs _0.1 FA _0.9 PbI ₃ solution by WAC-gel resin. (b) A plot of lead adsorption for a perovskite solution by three one-hour WAC- gel treatments. The perovskite solution was prepared by dissolving 10 delaminated perovskite solar modules in 20 mL DMF, wherein the module active area was ~25.0 cm ² . (c) XRD pattern of recycled PbI ₂ from Cs _0.1 FA _0.9 PbI ₃ solution, compared with XRD patterns of commercial PbI ₂ , FAI, and CsI. (d) PCE of perovskite solar cells fabricated with commercial PbI2 and recycled PbI2. The device size was 8 mm ² . (e) PCE of perovskite solar modules fabricated on fresh ITO/glass and recycled ITO/glass. The module active area was ~25.0 cm ² . (f) A plot of the lead adsorption of regenerated WAC-gel compared with fresh WAC-gel. Figure 5 shows two proposed lead recycling systems. Left: bath structure, which involves pre-lead absorption/desorption, followed by filtration; Right: column structure, where lead absorption and desorption proceed when solution or solvent flows through the column. Figure 6 shows a pseudo-first order kinetic fit for lead adsorption by WAC-gel resin. Figure 7A shows a bar graph of the lead adsorption ratio of a 4140 ppm lead-containing solution using different organic solvents and water. Figure 7B shows a bar graph of the lead adsorption ratio of a 4140 ppm lead-containing solution having a solvent of DMF:water=9:1 under different pH values. The lead adsorption treatment was carried out by stirring 10 mL 20 mM of a lead containing solution with 1 g WAC- gel resin under 400 rpm for 20 hours. DETAILED DESCRIPTION The subject matter described herein relates to cost-effective methods for recycling lead from lead waste. In certain embodiments, the lead waste is a lead-containing material. The lead in the lead-containing material can be regenerated as a lead halide for reuse. In certain embodiments, the lead-containing material is a lead-containing perovskite material harvested from a solar cell or solar module. Perovskite photovoltaic (PV) technologies are revolutionizing electricity generation through the application of metal halide perovskites (MHPs). ^1,2 Indeed, perovskite solar cell efficiencies have reached 25.5%, which are comparable to single crystal silicon-based PV cells. Additionally, perovskite/silicon tandem solar cells have already achieved a high certified efficiency of 29.5%. ³ Furthermore, the efficiencies of perovskite minimodules fabricated by scalable deposition methods are approaching 20%. ⁹ Defect-tolerant metal halide perovskites can be manufactured by low-cost solution processes, such as blade coating, slot-die coating, and spray coating. ^4-8 Many companies world-wide are commercializing perovskite PV through standalone single junction structures or through a combination of existing PV technology using tandem structures. ¹⁰ Efforts in industry and academia have focused on upscaling and enhancing module/cell efficiency and stability for perovskite PV. However, the most efficient metal halide perovskites for this purpose contain toxic lead, such as ^-FAPbI3, ^11,12 (FAPbI3)0.95(MAPbBr3)0.05, ¹³ MAxFA1- xPbI3, ^14,15 etc. Attempts to replace the lead in MHPs, such as though tin- or double-perovskite- based perovskite solar cells, have resulted in perovskites with much poorer stability and/or lower efficiency compared with their lead-containing counterparts. ^16,17,18 One gigawatt of solar PV capacity using perovskite solar panels having 20% efficiency and with a perovskite film thickness of 500 nm contains about 3.5 tons of lead. However, if 20% of the anticipated 8500 gigawatt PV market in 2050 is occupied by perovskite PV, perovskite solar panels would be expected to contain up to ~6000 tons of lead. ¹⁹ Lead adsorbing materials, such as P,P′-di(2-ethylhexyl)methanediphosphonic acid and sulfonic acid cation exchange resins, have been integrated into perovskite solar panels to prevent lead leakage from damaged perovskite solar modules. ^20-22 While these methods are useful for lead management during operation in the field, lead management for end-of-life perovskite solar modules is also a priority to ensure the future low-cost advantages of perovskite solar cells. It is a challenge to properly dispose of and recycle silicon solar panels. This is becoming more of an urgent undertaking, as the solar panels installed in the 2000s are reaching the end of their lifespan. ^23-25 While silicon solar panels contain many valuable materials (e.g. silicon, glass, silver, and aluminum), there is no cost-effective recycling technology to recover these materials. Consequently, most decommissioned silicon panels go to landfill. ^23-25 When it comes to lead-containing perovskite solar modules, going to landfill is not an option, as the toxic and water-soluble lead in the perovskite film poses a threat to the ecosystem and human health. As such, it is essential to develop a practical recycling technique, particularly lead recycling technique, for perovskite solar modules. ^26-30 Several lead removal methods have been investigated for wastewater treatment, such as chemical precipitation, electrodeposition, ion exchange, membrane separation, and adsorption. ^31-36 However, the before-mentioned methods are established for aqueous pollutants. Conversely, perovskite solar modules require organic solvents for high lead solubility and recycling capacity, for which a cost effective technique has not yet been developed. Park et al. disclosed iron-incorporated hydroxyapatite as an adsorbent for recovering lead from perovskite-containing organic solvents. ³⁷ However, Park’s method is not cost-effective for lead recycling as a result of the complicated iron-incorporated hydroxyapatite hollow composites applied in the method. Additionally, the adsorbent of Park cannot be reused because it dissolves during the lead release process. ³⁷ Disclosed herein is a low-cost recycling technique for perovskite solar modules that applies a carboxylic acid cation exchange resin as a lead adsorbent. The carboxylic acid cation exchange resin efficiently adsorbs lead ions from organic solvents and efficiently releases the adsorbed lead ions to clean solution by ion exchange between Pb ²⁺ ions and H ⁺ ions. Unlike former lead trapping studies that utilize a strongly acidic cation exchange resin having a sulfonic acid functional group, ^21,22 the weakly acidic cation exchange resins applied herein exhibit better lead recycling efficiency due to easy release of Pb ²⁺ ions from the carboxylic acid functional group. In the lead- recycling methods, the lead is precipitated from aqueous solution as recrystallized PbI2 for reuse following reaction with sodium iodide. In certain embodiments, the perovskite module recycling techniques described herein also make use of a thermal delamination process to disassemble an encapsulated solar module to remove front transparent conductor and back cover glass, as well as the photoactive perovskite layer. The glass substrates (i.e. the back cover glass and the transparent conductive oxide-coated glass), as well as the lead in the perovskite layer, can be recycled for reuse in future perovskite solar modules. In certain embodiments, the transparent conductive oxide-coated glass and/or glass substrates removed from the solar cell or solar module are used in the fabrication of a new solar cell or solar module. The presently disclosed subject matter will now be described more fully hereinafter. However, many modifications and other embodiments of the presently disclosed subject matter set forth herein will come to mind to one skilled in the art to which the presently disclosed subject matter pertains having the benefit of the teachings presented in the foregoing descriptions. Therefore, it is to be understood that the presently disclosed subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. In other words, the subject matter described herein covers all alternatives, modifications, and equivalents. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in this field. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In the event that one or more of the incorporated literatures, patents, and similar materials differs from or contradicts this application, including but not limited to defined terms, term usage, described techniques, or the like, this application controls. I. Definitions As used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”). As used herein, the term “about,” when referring to a measurable value such as an amount of a compound or agent of the current subject matter, dose, time, temperature, and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1%, ±0.5%, or even ±0.1% of the specified amount. As used herein, conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. As used herein, the term “active layer” or “photoactive layer” refers to a layer of a photoactive device, such as a solar cell or solar module, which absorbs the photons that are converted to electrical energy or which emit the photons which are formed in response to input electrical energy. In some embodiments, an active layer is the layer of a photoactive device which absorbs photons and exhibits a change in at least one property, such as resistance of the active layer. In a photovoltaic cell, an active layer may also be referred to as an absorber layer. A photoactive device may have more than one active layer. In some embodiments, an active layer of a photoactive device is a perovskite layer, or layer comprising a perovskite material. As used herein, the terms “power conversion efficiency,” “PCE,” “photovoltaic efficiency”, and “solar cell efficiency,” may be used interchangeably and refer to the ratio of energy output from the photovoltaic device to the energy input to the photovoltaic device. The energy output is in the form of electrical energy and energy input is in the form of electromagnetic radiation (e.g., sunlight). Unless otherwise indicated, the photovoltaic efficiency refers to terrestrial photovoltaic efficiency, corresponding to AM1.5 conditions, where AM is Air Mass. PCE may be measured by one or more techniques conventionally known to one of ordinary skill in the art. As used herein, the term “illumination equivalent to 1 sun” refers to an illumination (radiation) intensity and/or electromagnetic spectrum of illumination that substantially approximates or is substantially equivalent to terrestrial solar intensity and/or electromagnetic spectrum. As used herein, the term “perovskite material” refers to a material or compound that is characterized by a perovskite crystal structure. A perovskite material may be inorganic, such as, but not limited to, CsPbI3, wherein the chemical formula of the perovskite material does not comprise a carbon (C)-containing, organic functional group. A perovskite material may be organic-inorganic, such as, but not limited to, MAPbI3 (MA=CH3NH3 ⁺ ) and Cs0.1FA0.9PbI3 (FA=CH(NH2)2 ⁺ ), wherein the chemical formula of the perovskite material comprises organic and inorganic compounds/elements. As used herein, the term “metal halide perovskite” or “MHP” refers to a perovskite material with the general chemical formula ABX3. Here A is one or more monovalent cations (MA: CH ₃ NH ₃ ⁺ , FA: CH(NH ₂ ) ₂ ⁺ and Cs ⁺ ); B represents one or more divalent metal cations (Pb ²⁺ , Sn ²⁺ , or Cu ²⁺ ), and X is one or more halogen anions (Cl ^– , Br ^– , or I ^– ). The term “solubility”, as used herein, refers to the ability of a chemical species to dissolve in a liquid solvent(s), such as an organic solvent or water. As used herein, the term “solution” refers to a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent). As used herein, “contacting” refers to allowing two or more reagents to contact each other. The contact may or may not be facilitated by mixing, agitating, stirring, and the like. Nonlimiting examples of reagents include a lead-containing material, a solution, lead waste, an organic solvent, an exchange material, or an alkali metal halide solution. Additional definitions may be provided below. II. Methods for Preparing a Lead Halide or Recovering Lead from Lead Waste In one aspect, the subject matter described herein is directed to a method for preparing a lead halide, comprising: contacting a lead-containing material with an organic solvent to form a first solution; contacting the first solution with a weakly acidic cation exchange material, wherein the weakly acidic cation exchange material adsorbs Pb ²⁺ from the first solution to form a weakly acidic cation exchange material comprising Pb ²⁺ ; contacting the weakly acidic cation exchange material comprising Pb ²⁺ with an acid to produce a solution comprising a soluble lead compound; contacting the solution comprising a soluble lead compound with an alkali metal halide solution to prepare a second solution; and precipitating the lead halide. In another aspect, the subject matter described herein is directed to a method for recovering lead from lead waste, comprising: contacting the lead waste with an organic solvent to form a first solution; contacting the first solution with a weakly acidic cation exchange material, wherein the weakly acidic cation exchange material adsorbs Pb ²⁺ from the first solution to form a weakly acidic cation exchange material comprising Pb ²⁺ ; contacting the weakly acidic cation exchange material comprising Pb ²⁺ with an acid to produce a solution comprising a soluble lead compound; and contacting the solution comprising a soluble lead compound with an alkali metal halide solution to prepare a second solution; and precipitating a lead halide. In certain embodiments of the method for preparing a lead halide or recovering lead from lead waste, the contacting the first solution with a weakly acidic cation exchange material comprises: a) separating the weakly acidic cation exchange material comprising Pb ²⁺ from the first solution to prepare a Pb-diminished solution; b) contacting a weakly acidic cation exchange material with the Pb-diminished solution to form a solution 1A; and c) separating a weakly acidic cation exchange material comprising Pb ²⁺ from the solution 1A to form a Pb-diminished solution; wherein b and c can be repeated iteratively. In certain embodiments, steps b-c are useful for preparing a lead halide when the first solution comprises a high concentration of Pb ²⁺ . First solutions comprising a high Pb ²⁺ concentration of at least or about 10 PPM to about 1000 PPM (parts per million Pb ²⁺ ), for example, can benefit from multiple treatments with weakly acidic cation exchange materials. In certain embodiments, the first solution has a concentration of about 8500 PPM Pb ²⁺ , 8300 PPM Pb ²⁺ , 7500 PPM Pb ²⁺ , 6000 PPM Pb ²⁺ , 5000 PPM Pb ²⁺ , 3000 PPM Pb ²⁺ , 1000 PPM Pb ²⁺ , 900 PPM Pb ²⁺ , 800 PPM Pb ²⁺ , 700 PPM Pb ²⁺ , 600 PPM Pb ²⁺ , 500 PPM Pb ²⁺ , 400 PPM Pb ²⁺ , 300 PPM Pb ²⁺ , 200 PPM Pb ²⁺ , 100 PPM Pb ²⁺ , 75 PPM Pb ²⁺ , 50 PPM Pb ²⁺ , 25 PPM Pb ²⁺ , 15 PPM Pb ²⁺ , or 10 PPM Pb ²⁺ . The amount of Pb ²⁺ in the solution decreases after each contacting with a weakly acidic cation exchange material. The adsorption of the Pb ²⁺ on the weakly acidic cation exchange material is influenced by the number of active sites on the weakly acidic cation exchange material. As such, by contacting the solution iteratively with multiple weakly acidic cation exchange materials, more Pb ²⁺ can be adsorbed. The multiple weakly acidic cation exchange materials can be combined and then contacted with an acid to produce a solution comprising a soluble lead compound. In certain embodiments, the weakly acidic cation exchange material is of the same or different type in each iterative further processing. In certain embodiments, the further processing further comprises combining one or more of the weakly acidic cation exchange material comprising Pb ²⁺ . As used herein, “Pb-diminished solution” refers to a solution that once contained a certain concentration of Pb ²⁺ , and, after being contacted with a weakly acidic cation exchange material, which adsorbed Pb ²⁺ ions from the solution, now contains a lower concentration of Pb ²⁺ . It is therefore a “Pb-diminished solution.” In certain embodiments, after the one or more weakly acidic cation exchange materials comprising Pb ²⁺ are combined, they are contacted with the acid to produce a solution comprising a soluble lead compound. a. Lead-Containing Material or Lead Waste As used herein, “lead-containing material” or “lead waste” refers to a material or compound containing the element, lead. In certain embodiments, the lead-containing material or lead waste is PbI _2. In certain embodiments, the lead-containing material or lead waste is a lead- containing perovskite material harvested from a solar cell or solar module. As used herein, “harvested” from a solar cell or solar module refers to being “obtained from” a solar cell or solar module. Typically, the perovskite material harvested from a solar cell or solar module is in the form of a photoactive layer, and the solar cell or solar module has neared the end of its lifespan. In certain embodiments of the method for preparing a lead halide or for recovering lead from lead waste, the lead-containing perovskite material harvested from a solar cell or solar module is contacted with a first solvent, such as chlorobenzene or dichlorobenzene, prior to contacting with an organic solvent. The purpose of contacting the lead-containing perovskite material with a first solvent is to remove any remaining electron transport or buffer layer C60 or BCP that may remain on the perovskite prior to contacting with an organic solvent. After contacting with the first solvent, the perovskite is removed from the first solvent and contacted with the organic solvent to form the first solution. In certain embodiments of the lead-containing perovskite material, the lead-containing perovskite material is a composition of Formula (I) wherein, y is between 0 and 0.9; M is a metal; A is one or more cations selected from the group consisting of methylammonium (MA), tetramethylammonium, formamidinium (FA), Cs ⁺ , Rb ⁺ , K ⁺ , Na ⁺ , butylammonium, phenethylammonium, phenylammonium, guanidinium, ammonium; and X is one or more halides selected from the group consisting of Cl-, I-, Br-, and I-. In certain embodiments of the lead-containing perovskite material, the lead-containing perovskite material is a composition of Formula (Ia) wherein, A is one or more cations selected from the group consisting of methylammonium (MA), tetramethylammonium, formamidinium (FA), Cs ⁺ , Rb ⁺ , K ⁺ , Na ⁺ , butylammonium, phenethylammonium, phenylammonium, guanidinium, ammonium; and X is one or more halides selected from the group consisting of Cl-, I-, Br-, and I-. In certain embodiments, A may comprise an ammonium, an organic cation of the general formula [NR4] ⁺ where the R groups can be the same or different groups. Suitable R groups include, but are not limited to: methyl, ethyl, propyl, butyl, pentyl group or isomer thereof; any alkane, alkene, or alkyne C _x H _y , where x=1-20, y=1-42, cyclic, branched or straight-chain; alkyl halides, C _x H _y X _z , x=1-20, y=0-42, z=1-42, X=F, Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes where at least one nitrogen is contained within the ring (e.g., pyridine, pyrrole, pyrrolidine, piperidine, tetrahydroquinoline); any sulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group (nitroxide, amine); any phosphorous containing group (phosphate); any boron-containing group (e.g., boronic acid); any organic acid (e.g., acetic acid, propanoic acid); and ester or amide derivatives thereof; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histindine, 5-ammoniumvaleric acid) including alpha, beta, gamma, and greater derivatives; any silicon containing group (e.g., siloxane); and any alkoxy or group, —OCxHy, where x=0-20, y=1-42. In certain embodiments, A is methylammonium, (CH ₃ NH ₃ ⁺ ). In certain embodiments, A is tetramethylammonium, ((CH ₃ ) ₄ N ⁺ ). In certain embodiments, A is butylammonium, which may be represented by (CH3(CH2)3NH3 ⁺ ) for n-butylammonium, by ((CH3)3CNH3 ⁺ ) for t-butylammonium, or by (CH3)2CHCH2NH3 ⁺ ) for iso-butylammonium. In certain embodiments, A is phenethylammonium, which may be represented by C ₆ H ₅ (CH ₂ ) ₂ NH ₃ ⁺ or by C6H5CH(CH3)NH3 ⁺ . In certain embodiments, A comprises phenylammonium, C6H5NH3 ⁺ . In certain embodiments, A may comprise a formamidinium, an organic cation of the general formula [R ₂ NCHNR ₂ ] ⁺ where the R groups can be the same or different groups. Suitable R groups include, but are not limited to: hydrogen, methyl, ethyl, propyl, butyl, pentyl or an isomer thereof; any alkane, alkene, or alkyne CxHy, where x=1-20, y=1-42, cyclic, branched or straight-chain; alkyl halides, C _x H _y X _z , x=1-20, y=0-42, z=1-42, X=F, Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes where at least one nitrogen is contained within the ring (e.g., imidazole, benzimidazole, dihydropyrimidine, (azolidinylidenemethyl)pyrrolidine, triazole); any sulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group (nitroxide, amine); any phosphorous containing group (phosphate); any boron-containing group (e.g., boronic acid); any organic acid (acetic acid, propanoic acid) and ester or amide derivatives thereof; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histindine, 5-ammoniumvaleric acid) including alpha, beta, gamma, and greater derivatives; any silicon containing group (e.g., siloxane); and any alkoxy or group, —OC _x H _y , where x=0-20, y=1-42. In certain embodiments A is a formamidinium ion represented by (H2N═CH—NH2 ⁺ ). In certain embodiments, A may comprise a guanidinium, an organic cation of the general formula [(R ₂ N) ₂ C═NR ₂ ] ⁺ where the R groups can be the same or different groups. Suitable R groups include, but are not limited to: hydrogen, methyl, ethyl, propyl, butyl, pentyl group or isomer thereof; any alkane, alkene, or alkyne CxHy, where x=1-20, y=1-42, cyclic, branched or straight-chain; alkyl halides, C _x H _y X _z , x=1-20, y=0-42, z=1-42, X=F, Cl, Br, or I; any aromatic group (e.g., phenyl, alkylphenyl, alkoxyphenyl, pyridine, naphthalene); cyclic complexes where at least one nitrogen is contained within the ring (e.g., octahydropyrimido[1,2-a]pyrimidine, pyrimido[1,2-a]pyrimidine, hexahydroimidazo[1,2-a]imidazole, hexahydropyrimidin-2-imine); any sulfur-containing group (e.g., sulfoxide, thiol, alkyl sulfide); any nitrogen-containing group (nitroxide, amine); any phosphorous containing group (phosphate); any boron-containing group (e.g., boronic acid); any organic acid (acetic acid, propanoic acid) and ester or amide derivatives thereof; any amino acid (e.g., glycine, cysteine, proline, glutamic acid, arginine, serine, histindine, 5-ammoniumvaleric acid) including alpha, beta, gamma, and greater derivatives; any silicon containing group (e.g., siloxane); and any alkoxy or group, —OCxHy, where x=0-20, y=1-42. In certain embodiments, A is a guanidinium ion of the type (H ₂ N═C—(NH ₂ ) ₂ ⁺ ). In certain embodiments, A may comprise an alkali metal cation, such as Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , or Cs ⁺ . In embodiments, M is a metal. In certain embodiments, M can be one or more elements from Group 14 of the Periodic Table comprising tin, germanium, or one or more transition metal elements from Groups 3-12 of the Periodic Table (e.g., titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, palladium, platinum, and cadmium), and/or one or more alkaline earth elements (e.g., magnesium, calcium, strontium, and barium). In certain embodiments, M is selected from the group consisting of tin, cadmium, germanium, zinc, nickel, platinum, palladium, mercury, titanium, and silicon. In certain embodiments, M is tin. In certain embodiments, the variable X is independently selected from one or a combination of chloride, bromide, fluoride, iodide, and thiocyanate. In certain embodiments, X is selected from the group consisting of SCN-, BF4-, F-, Cl-, Br-, I-, and a combination thereof. In certain embodiments, X is a halide selected from the group consisting of F-, Cl-, Br-, I-, and a combination thereof. In certain embodiments, the A unit in Formula (I) or Formula (Ia) is occupied by two or more different cations. In certain embodiments, the perovskite crystal structure composition may be doped (e.g., by partial substitution of the cation A, and/or Pb (or M)) with a doping element, which may be, for example, an alkali metal (e.g., Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , or Cs ⁺ ), an alkaline earth metal (e.g., Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ ) or other divalent metal, such as provided for M or Pb ²⁺ , but different from M or Pb ²⁺ (e.g., Sn ²⁺ , Zn ²⁺ , Cd ²⁺ , Ge ²⁺ , Ni ²⁺ , Pt ²⁺ , Pd ²⁺ , Hg ²⁺ , Si ²⁺ , Ti ²⁺ ), or a Group 15 element, such as Sb, Bi, As, or P, or other metals, such as silver, copper, gallium, indium, thallium, molybdenum, or gold, typically in an amount of up to or less than about 1, 5, 10, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 mol% of A, Pb, or M. A may comprise a mixture of cations. Pb or M may comprise a mixture of cations. In certain embodiments of Formula (I) y is 0. In certain embodiments of Formula (I), X is I-. In certain embodiments of Formula (I), A is Cs ⁺ , formamidinium (FA), or a combination thereof. In certain embodiments of Formula (Ia), A is Cs ⁺ , formamidinium (FA), or a combination thereof; and X is I-. In certain embodiments of Formula (I) or (Ia), the lead-containing perovskite material is a composition of Cs _x FA _1-x PbI ₃ , wherein x is between 0 and 0.9. In certain embodiments, x is 0.9, 0.8, 0.7, 0.6, 0.5, 0.3, 0.2, or 0.1. In certain embodiments, the lead-containing perovskite material is a composition of Cs0.1FA0.9PbI3. b. Delamination Process In certain embodiments of the method for preparing a lead halide or for recovering lead from lead waste, prior to contacting the lead-containing material or the lead waste with an organic solvent to form a first solution, separating transparent conductive oxide-coated glass and/or glass substrates from the solar cell or solar module, wherein the separating comprises: heating the solar cell or solar module at a sufficient temperature to melt an encapsulant disposed on the solar cell or solar module; and removing the transparent conductive oxide-coated glass and/or glass substrates from the solar cell or solar module. In certain embodiments of the separating, the heating is at a temperature between about 100 °C and 400 °C. In certain embodiments, the heating is at a temperature of about 240 °C, 241 °C, 242 °C, 243 °C, 244 °C, 245 °C, 246 °C, 247 °C, 248 °C, 249 °C, 250 °C, 251°C, 252 °C, 253 °C, 254 °C, 255 °C, 256 °C, 257 °C, 258 °C, 259 °C, or 260 °C. In certain embodiments of the separating, the heating proceeds for about 10 seconds to about 60 minutes, about 10 seconds to about 45 minutes, about 10 seconds to about 30 minutes, about 10 seconds to about 30 minutes, about 10 seconds to about 20 minutes, about 10 seconds to about 10 minutes, about 10 seconds to about 5 minutes, about 1 minute to about 3 minutes, about 30 seconds to about 1 minute, or about 45 seconds to about 2.5 minutes. In certain embodiments of the separating, the heating proceeds for about 1, 2, or 3 minutes. In certain embodiments of the separating, the encapsulant is selected from the group consisting of epoxy resin, polyolefin, ethyl vinyl acetate, ethylene acid copolymer ionomer, polyisobutylene, and polyurethane. In certain embodiments of heating the solar cell or solar module at a sufficient temperature to melt an encapsulant disposed on the solar cell or solar module, the melting proceeds at an interface in the cell or module. In certain embodiments, the melting proceeds at the interface of an electron transport layer and metal electrode, where adhesion is often weaker compared to other interfaces. In certain other embodiments, melting proceeds at a metal electrode-encapsulant interface. In certain other embodiments, melting proceeds at other locations in the solar cell or solar module. In certain embodiments of removing the transparent conductive oxide-coated glass and/or glass substrates from the solar cell or solar module, the method further comprises removing hole transport layer(s), electron transport layer(s), buffer layer(s), electrode(s), and/or encapsulant from the transparent conductive oxide-coated glass and/or glass substrates. In certain embodiments, this “removing” comprises scraping encapsulant and/or metal electrode with a device, such as a knife off of the transparent conductive oxide-coated glass and/or glass substrates. In certain other embodiments, this “removing” comprises washing the transparent conductive oxide-coated glass and/or glass substrates with one or more solvents, such as water, isopropanol, or acetone to remove a hole transport layer, such as PTAA. In certain embodiments, the transparent conductive oxide- coated glass substrate is ITO disposed on glass. In certain embodiments, the glass substrate is a cover glass for a solar cell or solar module. c. Organic Solvents In certain embodiments of the method for preparing a lead halide or for recovering lead from lead waste, the organic solvent is selected from one or more of acetone, benzene, Chlorobenzene, Acetic acid, Chloroform, 2-butanone, 1-butanol, 2-butanol, p-xylene, o-xylene, Ethanol, Ethyl acetate, Ethylene glycol, dimethylformamide (DMF), pyridine, toluene, pentane, 1-propanol, nitromethane, methanol, hexane, methylene chloride, ether (MTBE), triethyl amine, N-methyl-2-pyrrolidinone (NMP), tetrahydrofuran (THF), carbon tetrachloride, cyclohexane, diethyl ether, diethylene glycol, glycerin, heptane, dimethyl sulfoxide (DMSO), acetonitrile, t- butyl alcohol, dimethylether, diglyme (diethylene glycol dimethyl ether), 1,2-dimethoxy-ethane (glyme, DME), 2-propanol, 1,2-dichloroethane, dioxane, hexamethylphosphorous triamide (HMPT), hexamethylphosphoramide (HMPA), N-methyl-2-pyrrolidone, dimethylacetamide, 2- methoxyethanol, γ-butyrolactone, N,N-diethylformamide, and N,N′-Dimethylpropyleneurea. d. Weakly Acidic Cation Exchange Material Ion exchange is the reversible interchange of ions between a solid (ion exchange material) and a liquid in which there is no permanent change in the structure of the solid. Ion exchange is used in water treatment and also provides a method of separation in many non-water processes. Weak acid cation exchange resins are based primarily on acrylic or methacrylic acid that has been cross-linked with a di-functional monomer, such as divinylbenzene [DVB]. The weakly acidic cation exchange materials described herein are materials that can sufficiently absorb Pb ²⁺ ions from solutions comprising Pb ²⁺ ions, as well as easily release the Pb ²⁺ ions when contacted with an acid. In certain embodiments, the weakly acidic cation exchange material is a carboxylic acid weakly acidic cation exchange resin gel (WAC-gel) (hydrogen-type), which is commercially available from RESINTECH. In certain other embodiments, the weakly acidic cation exchange material is a hydrogen form macroporous weak acid cation resin (WACMP), which is also commercially available from RESINTECH. e. Acid After the weakly acidic cation exchange material adsorbs Pb ²⁺ ions from the first solution to form a weakly acidic cation exchange material comprising Pb ²⁺ , the weakly acidic cation exchange material undergoes regeneration by contacting the weakly acidic cation exchange material comprising Pb ²⁺ with an acid to release the Pb ²⁺ ions. In certain embodiments, the acid has a pK _a lower than the weakly acidic cation exchange material. In certain embodiments, the weakly acid cation exchange material has a pKa of about 5-6, and the acid has a pka less than 5-6. In certain embodiments, the acid has a pKa of about 4 to -7. In certain embodiments, the acid is selected from the group consisting of HNO ₃ , HCl, HBr, H ₂ SO ₄ , and CH ₃ COOH. In certain embodiments, the acid is selected based on its ability to both regenerate the weakly acidic cation exchange material (release Pb ²⁺ ions from the weakly acidic cation exchange material), as well as form a solution comprising a soluble lead compound. In certain embodiments, the acid is HNO ₃ . In certain embodiments, the HNO ₃ has a concentration of about 0.01 M to about 2 M. In certain embodiments, the HNO3 has a concentration of about 0.13 M, 0.14 M, 0.15 M, 0.16 M, 0.17 M, 0.18 M, 0.19 M, 0.20 M, 0.21 M, 0.22 M, 0.23 M, 0.24 M, 0.25 M, 0.50 M, 0.75 M, 1.0 M, 1.25 M, 1.50 M, or 1.75 M. In certain embodiments, the HNO ₃ has a concentration of at least 0.16 M. In certain embodiments, the acid is HNO3 and the solution comprising a soluble lead compound is a lead(II) nitrate solution, Pb(NO3)2. f. Alkali Metal Halide Solution In certain embodiments of the methods for preparing a lead halide or for recovering lead from lead waste described herein, the solution comprising a soluble lead compound is contacted with an alkali metal halide solution to prepare a second solution, followed by precipitating the lead halide. In certain embodiments, the alkali metal halide solution is selected from the group consisting of LiI solution, NaI solution, LiBr solution, NaBr solution, LiCl solution, NaCl solution, KI solution, KBr solution, and KCl solution. In certain embodiments, the alkali metal halide solution is a NaI solution. In certain embodiments, the alkali metal halide solution is an aqueous NaI solution having a concentration of about 1.2, 1.3, 1.4, 1.5, 1.6, or 1.7 M. In certain embodiments, the lead halide that is precipitated is PbBr2, PbCl2, or PbI2. In certain embodiments, the lead halide that is precipitated is PbI2. The lead halide forms as a precipitate upon combining the solution comprising a soluble lead compound with the alkali metal halide solution to form the second solution. In embodiments, precipitating the lead halide comprises filtering the lead halide precipitate from the second solution, such as through vacuum filtration. g. Economical Production of Reusable Lead As described herein, the methods for preparing a lead halide or for recovering lead from lead waste allow for the economical production of reusable lead. As used herein, “reusable lead” refers to lead that can be used again or more than once. In certain embodiments, the reusable lead is lead that can be used at least two, three, four, or five times. In embodiments, the reusable lead is harvested from a lead-containing perovskite material in a solar cell or solar module, which then undergoes a chemical treatment process (the lead waste recovery or lead halide preparation methods described herein) to produce the reusable lead in the form of a lead halide, such as PbI2. This lead halide can then be used in the preparation of a lead-containing perovskite material for use in a solar cell or solar module. Once the solar cell or solar module reaches the end of its lifetime, the lead-containing perovskite material in the solar cell or module is harvested for reuse according to the lead halide or lead waste recovery methods described herein. “Economical production” of reusable lead refers to the cost-effective methods described herein for recovering lead waste or for preparing a lead halide from a lead-containing material. As shown in Table 1, the methods described herein for the recovery and reuse of lead, organic solvent, and glass substrates for solar cells and solar modules allow for significant cost savings. In certain embodiments, according to the methods described herein, at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9% of the lead present in the lead-containing material or lead waste is precipitated in the lead halide. Furthermore, as shown in the Examples, perovskite solar cells or solar modules fabricated from the reusable lead and/or transparent conductive oxide-coated glass and/or glass substrates exhibit power conversion efficiencies similar to solar cells or solar modules fabricated using new materials. III. Solar Cells and Solar Modules As used herein, a “solar cell” is understood to be a basic building block of a “solar module.” A solar module can contain two or more solar cells. In embodiments, the solar cells and solar modules can be fabricated or delaminated according to the methods disclosed herein. In certain embodiments, the solar cells comprise an anode, a cathode, and a perovskite photoactive layer. In certain embodiments, the solar cells further comprise one or more transport layers, such as an electron transport layer and/or a hole transport layer. In certain embodiments, the cathode and anode are each individually selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, radium, boron, aluminum, gallium, indium, thallium, tin, lead, flerovium, bismuth, antimony, tellurium, polonium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, rutherfordium, dubnium, seaborgium, bohrium, hassium, copernicium, samarium, neodymium, ytterbium, an alkali metal fluoride, an alkaline-earth metal fluoride, an alkali metal chloride, an alkaline-earth metal chloride, an alkali metal oxide, an alkaline-earth metal oxide, a metal carbonate, a metal acetate, carbon nanowire, carbon nanosheet, carbon nanorod, carbon nanotube, graphite, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum doped zinc oxide (AZO), antimony-tin mixed oxide (ATO), zinc-indium-tin oxide (ZITO), and network of metal/alloy nanowire, or a combination of two or more of the above materials. In certain embodiments, the hole transport layer comprises at least one of poly(3,4- ethylene dioxithiophene) (PEDOT) doped with poly(styrene sulfonic acid) (PSS), Spiro- OMeTAD, pm-spiro-OMeTAD, po-spiro-OMeTAD, dopants in spiro-OMeTAD, 4,4'- biskptrichlorosilylpropylphenyl)pheny laminoThiphenyl (TPD-Si2), poly(3-hexyl-2,5-thienylene vinylene) (P3HTV), C60, carbon, carbon nanotube, graphene quantum dot, graphene oxide, copper phthalocyanine (CuPc), Polythiophene, poly(3,4- (1hydroxymethyl)ethylenedioxythiophene (PHMEDOT), n-dodecylbenzenesulfonic acid/hydrochloric acid doped poly(aniline) nanotubes (a-PANIN)s, poly(styrene sulfonic acid)- graft-poly(aniline) (PSSA-g-PANI), poly(9.9-dioctylfluorene)-co-N-(4-(1-methylpropyl)phenyl) diphenylamine (PFT), 4,4'-bis(p- trichlorosilylpropylphenyl) phenylaminobiphenyl (TSPP), 5,5'- bis(p-trichlorosilylpropylphenyl) phenylamino-2,20 bithiophene (TSPT), N- propyltriethoxysilane, 3,3,3-trifluo ropropyltrichlorosilane or 3-aminopropyltriethoxysilane, Poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) (PTAA), (Poly[[(2,4-dimethylphenyl)imino]- 1,4-phenylene(9,9-dioctyl-9H-fluorene-2,7-diyl)-1,4phenylene ], (PF8-TAA)), (Poly [[(2,4- dimethylphenyl)imino]-1,4-phenylene (6,12-dihydro-6,6,12,12tetraoctylindeno[1,2-b]fluorene- 2,8-diyl)-1,4-phenylene]) (PIF8-TAA), poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5- b]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]t hieno[3,4-b]thiophenediyl]] (PTB7), poly[N-90-heptadecanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thi enyl-20,10,30-benzothiadiazole)] (PCDTBT), Poly[2,5-bis(2-decyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H) -dione-(E)-1,2- di(2,20-bithiophen-5-yl) ethene] (PDPPDBTE), 4,8-dithien-2-yl-benzo[1,2- d ;4,5- d ′]bistriazole- alt -benzo[1,2- b :4,5b′]dithiophenes (pBBTa-BDTs), pBBTa-BDT1, pBBTa-BDT2 polymers, poly(3-hexylthiophene) (P3HT), poly(4,4’-bis(N-carbazolyl)-1,1’-biphenyl) (PPN), triarylamine (TAA) and/or thiophene moieties, Paracyclophane, Triptycene, and Bimesitylene, Thiophene and Furan-based hole transport materials, Dendrimer-like and star-type hole transport materials, VO, VOX, MoC, WO, ReO, NiOx, AgOx, CuO, Cu2O, V2O5, CuI, CuS, CuInS2, colloidal quantum dots, lead sulphide (PbS), CuSCN, Cu ₂ ZnSnS ₄ , Au nanoparticles and their derivatives. Thiophene derivatives, Triptycene derivatives, Triazine derivatives, Porphyrin derivatives, Triphenylamine derivatives, Tetrathiafulvalene derivatives, Carbazole derivatives and Phthalocyanine derivatives. As used herein, when a material is referred to a “derivate” or as “derivatives,” such as Triphenylamine derivatives, the material contains Triphenylamine in its backbone structure. In certain embodiments, the hole transport layer is selected from the group consisting of PTAA, Poly-TPD, Spiro-OMeTAD, PEDOT:PSS, NiO, MoO3, V2O5, EH44, and a combination thereof. In certain embodiments, the electron transport layer comprises at least one of LiF, CsP, LiCoO, CsCO, TiOX, TiO, nanorods (NRs), ZnO, ZnO nanorods (NRs), ZnO nanoparticles (NPs), ZnO, Al-O, CaO, bathocuproine (BCP), copper phthalocyanine (CuPc), pentacene, pyronin B, pentadecafluorooctyl phenyl-C60-butyrate (F-PCBM), C60, C60/LiF, ZnO NRS/PCBM, ZnO/cross-linked fullerene derivative (C-PCBSD), single walled carbon nanotubes (SWCNT), poly(ethylene glycol) (PEG), poly(dimethylsi loxane-block-methyl methacrylate) (PDMS-b-PMMA), polar polyfluorene (PF-EP), polyfluorene bearing lateral amino groups (PFN), polyfluorene bearing quaternary ammonium groups in the side chains (WPF-oxy-F), polyfluorene bearing quaternary ammonium groups in the side chains (WPF-6-oxy-F), fluorene alternating and random copolymer bearing cationic groups in the alkyl side chains (PFNBr DBT15), fluorene alternating and random copolymer bearing cationic groups in the alkyl side chains (PFPNBr), poly (ethylene oxide) (PEO), and fullerene derivatives. In certain embodiments, the electron transport layer is selected from the group consisting of C60, BCP, TiO2, SnO2, PCBM, ICBA, ICMA, ZnO, ZrAcac, LiF, TPBI, PFN, and a combination thereof. The solar cells or solar modules described herein can further comprise an encapsulant. The presence of an encapsulant can help prevent moisture from permeating the solar cell or module. In certain embodiments, the encapsulant is adjacent to a glass substrate in the solar cell or module, which can be affixed to the backside and/or front of the cell or module. As used herein, the “the back of the solar cell or solar module” or “backside” refers to the side of the cell or module that is shaded, largely facing away from the light source. The front side of the solar cell refers to the side which faces the light source. In certain embodiments, the encapsulant is selected from the group consisting of epoxy resin, polyolefin, ethyl vinyl acetate, ethylene acid copolymer ionomer, polyisobutylene, and polyurethane. As described above, the solar cells or solar modules described herein can further comprise one or more glass substrates. In certain embodiments, an encapsulant is disposed on a glass substrate, wherein the glass substrate faces the backside of the module or cell. In certain embodiments, a transparent conductive oxide, such as ITO, is coated on a glass substrate, wherein the glass substrate is affixed to the front of the cell or module. The subject matter described herein is directed to the following embodiments: 1. A method for preparing a lead halide, comprising: contacting a lead-containing material with an organic solvent to form a first solution; contacting said first solution with a weakly acidic cation exchange material, wherein said weakly acidic cation exchange material adsorbs Pb ²⁺ from said first solution to form a weakly acidic cation exchange material comprising Pb ²⁺ ; contacting said weakly acidic cation exchange material comprising Pb ²⁺ with an acid to produce a solution comprising a soluble lead compound; contacting said solution comprising a soluble lead compound with an alkali metal halide solution to prepare a second solution; and precipitating said lead halide. 2. The method of embodiment 1, wherein said lead-containing material is a lead-containing perovskite material harvested from a solar cell or solar module. 3. The method of embodiment 1, wherein, prior to contacting said lead-containing material with an organic solvent to form said first solution, separating transparent conductive oxide- coated glass and/or glass substrates from said solar cell or solar module, wherein said separating comprises: heating said solar cell or solar module at a sufficient temperature to melt an encapsulant disposed on said solar cell or solar module; and removing said transparent conductive oxide-coated glass and/or glass substrates from said solar cell or solar module. 4. The method of embodiment 1, wherein said organic solvent is selected from the group consisting of dimethylformamide, N-methyl-2-pyrrolidone, dichloromethane, acetonitrile, dimethyl sulfoxide, dimethylacetamide, 2-methoxyethanol, γ-butyrolactone, N,N- diethylformamide, and N,N′-Dimethylpropyleneurea, or mixtures thereof. 5. The method of embodiment 1 or 4, wherein said organic solvent comprises dimethylformamide. 6. The method of any one of embodiments 1-5, wherein said weakly acidic cation exchange material is a carboxylic acid exchange resin gel or carboxylic acid exchange resin microporous matrix material. 7. The method of embodiment 6, wherein said weakly acidic cation exchange material is a carboxylic acid exchange resin gel. 8. The method of embodiment 1, wherein said acid has a pKa lower than said weakly acidic cation exchange material. 9. The method of any one of embodiments 1-8, wherein said acid is selected from the group consisting of HNO3, HCl, HBr, H2SO4, and CH3COOH. 10. The method of any one of embodiments 1-9, wherein said acid is HNO3. 11. The method of embodiment 1, wherein said alkali metal halide solution is selected from the group consisting of LiI solution, NaI solution, LiBr solution, NaBr solution, LiCl solution, NaCl solution, KI solution, KBr solution, and KCl solution. 12. The method of embodiment 1 or 11, wherein said alkali metal halide solution is NaI solution. 13. The method of embodiment 1, wherein said lead halide is PbI2. 14. The method of embodiment 1, wherein said contacting said first solution with a weakly acidic cation exchange material comprises: a) separating said weakly acidic cation exchange material comprising Pb ²⁺ from said first solution to prepare a Pb-diminished solution; b) contacting a weakly acidic cation exchange material with said Pb-diminished solution to form a solution 1A; and c) separating a weakly acidic cation exchange material comprising Pb ²⁺ from said solution 1A to form a Pb-diminished solution; wherein b and c can be repeated iteratively. 15. The method of embodiment 14, wherein said weakly acidic cation exchange material is of the same or different type in each iterative further processing. 16. The method of embodiment 14 or 15, wherein said further processing further comprises combining one or more of said weakly acidic cation exchange material comprising Pb ²⁺ . 17. The method of embodiment 3, wherein said encapsulant is selected from the group consisting of epoxy resin, polyolefin, ethyl vinyl acetate, ethylene acid copolymer ionomer, polyisobutylene, and polyurethane. 18. The method of embodiment 3, wherein said temperature is between about 100 °C and 400 °C. 19. The method of embodiment 3 or 18, wherein said temperature is about 250 °C. 20. The method of embodiment 3, wherein said heating proceeds for about 10 seconds to about 60 minutes. 21. The method of embodiment 1, wherein at least 90% of the lead present in said lead- containing material is precipitated in said lead halide. 22. The method of embodiment 21, wherein at least 95% of the lead present in said lead- containing material is precipitated in said lead halide. 23. The method of embodiment 21, wherein at least 99% of the lead present in said lead- containing material is precipitated in said lead halide. 24. The method of embodiment 1 or 2, wherein said lead-containing perovskite material is a composition of Formula (I) wherein, y is between 0 and 0.9; M is a metal; A is one or more cations selected from the group consisting of methylammonium (MA), tetramethylammonium, formamidinium (FA), Cs ⁺ , Rb ⁺ , K ⁺ , Na ⁺ , butylammonium, phenethylammonium, phenylammonium, guanidinium, ammonium; and X is one or more halides selected from the group consisting of Cl-, I-, Br-, and I-. 25. The method of embodiment 24, wherein y is 0. 26. The method of embodiment 24, wherein X is I-. 27. The method of embodiment 24, wherein A is Cs ⁺ , formamidinium (FA), or a combination thereof. 28. The method of embodiment 1, wherein: said lead containing-material is a lead-containing perovskite material harvested from a solar cell or solar module; said lead-containing perovskite material is a composition of Formula (Ia) wherein, A is Cs ⁺ , formamidinium (FA), or a combination thereof; and X is I-; said organic solvent is dimethylformamide; said weakly acidic cation exchange material is a carboxylic acid exchange resin gel; said acid is HNO ₃ ; said alkali metal halide solution is NaI solution; and, said lead halide is PbI2. 29. The method of embodiment 28, wherein said composition of Formula (Ia) is Cs0.1FA0.9PbI3. 30. The method of embodiment 28, wherein, prior to contacting said lead-containing material with an organic solvent to form said first solution, separating transparent conductive oxide- coated glass and glass substrates from said solar cell or solar module, wherein said separating comprises: heating said solar cell or solar module at about 250 °C for about 2 minutes to melt an epoxy resin encapsulant disposed on said solar cell or solar module; and, removing said transparent conductive oxide-coated glass and glass substrates from said solar cell or solar module. 31. The method of embodiment 1, wherein said method is an economical production of reusable lead. 32. A method for recovering lead from lead waste, comprising: contacting said lead waste with an organic solvent to form a first solution; contacting said first solution with a weakly acidic cation exchange material, wherein said weakly acidic cation exchange material adsorbs Pb ²⁺ from said first solution to form a weakly acidic cation exchange material comprising Pb ²⁺ ; contacting said weakly acidic cation exchange material comprising Pb ²⁺ with an acid to produce a solution comprising a soluble lead compound; and contacting said solution comprising a soluble lead compound with an alkali metal halide solution to prepare a second solution; and precipitating a lead halide. 33. The method of embodiment 32, wherein said organic solvent is selected from the group consisting of dimethylformamide, N-methyl-2-pyrrolidone, dichloromethane, acetonitrile, dimethyl sulfoxide, dimethylacetamide, 2-methoxyethanol, γ-butyrolactone, N,N- diethylformamide, and N,N′-Dimethylpropyleneurea, or mixtures thereof. 34. The method of embodiment 32 or 33, wherein said organic solvent comprises dimethylformamide. 35. The method of embodiment 32, wherein said weakly acidic cation exchange material is a carboxylic acid exchange resin gel or carboxylic acid exchange resin microporous matrix material. 36. The method of embodiment 35, wherein said weakly acidic cation exchange material is a carboxylic acid exchange resin gel. 37. The method of embodiment 32, wherein said acid has a pKa lower than said weakly acidic cation exchange material. 38. The method of embodiment 32 or 37, wherein said acid is selected from the group consisting of HNO3, HCl, HBr, H2SO4, and CH3COOH. 39. The method of embodiment 32, 37, or 38, wherein said acid is HNO ₃ . 40. The method of embodiment 32, wherein said alkali metal halide solution is selected from the group consisting of LiI solution, NaI solution, LiBr solution, NaBr solution, LiCl solution, NaCl solution, KI solution, KBr solution, and KCl solution. 41. The method of embodiment 40, wherein said alkali metal halide solution is NaI solution. 42. The method of embodiment 32, wherein said lead halide is PbI2. 43. The method of embodiment 3, wherein said transparent conductive oxide-coated glass and/or glass substrates removed from said solar cell or solar module are used in the fabrication of a new solar cell or solar module. The following examples are offered by way of illustration and not by way of limitation. EXAMPLES Example 1: Roadmap for Recycling Lead and Glass Substrates A roadmap for recycling toxic lead and valuable glass substrates from perovskite solar modules is provided in Figure 1. After encapsulated perovskite solar modules were delaminated, the lead in the perovskite layer was dissolved by an organic solvent, such as dimethylformamide (DMF). Lead ions were first adsorbed by a lead adsorbent to fully remove lead from the organic solvent, and then released to clean solvent, followed by precipitation to PbI ₂ for reuse. A carboxylic acid cation exchange resin was selected as an adsorbent to recycle lead in decommissioned perovskite solar modules. The lead adsorption process and lead release process on resins are based on ion exchange principles. The cation exchange resin has a higher affinity for Pb ²⁺ than for H ⁺ . ^21,22,32 When the perovskite-containing organic solution contacts the cation exchange resin, the Pb ²⁺ ions can be adsorbed by the resin via ion exchanging with H ⁺ ions: It is noted that the ion exchange process is a reversible reaction. A high concentration of H ⁺ ions in solution could reverse the equilibrium in equation (1), which is a resin regeneration process and thus can be used for lead release. Possible regenerants for cation exchange resins are high concentration HCl or H2SO4 acid solutions. Regeneration by HCl and H2SO4 could directly precipitate the released Pb ²⁺ ions as PbCl ₂ and Pb(SO ₄ ) ₂ , which are both generally known to have low solubility in aqueous solution. Using HCl or H ₂ SO ₄ as regenerants could therefore pose challenges for lead release. As such, HNO3 aqueous solution was used as a regenerant to release the adsorbed lead ions as water-soluble Pb(NO3)2. PbI ₂ is one of the main lead sources for preparing highly efficient perovskite solar cells. As such, PbI ₂ was selected as a material to regenerate using recycled lead from the perovskite solar modules. Therefore, in the roadmap, the lead is converted from Pb(NO3)2 to PbI2 through the addition of low-cost NaI to the solution. Example 2: Delamination To recycle end-of-life perovskite solar modules, a delamination technique was first established to disassemble the encapsulated modules and expose the perovskite layer. As shown in the examples herein, the perovskite module structure was fabricated on indium tin oxide (ITO) glass and encapsulated with another piece of glass and encapsulant. An encapsulant for a perovskite solar cell, such as epoxy resin, polyolefin, Surlyn, polyisobutylene, or polyurethane, together with a back cover glass, can effectively prevent the permeation of moisture, oxygen and other hazards. ^38-41 It was discovered that a short thermal treatment at a high temperature allows for the disassembly of encapsulated perovskite solar modules and recovery of both intact ITO glass and back cover glass. After thermal stress at 250 °C for 2 min, the polymer encapsulant melted, which created a strain for the delamination of the perovskite solar module at an interface of the electron-transport-layer and metal-electrode (Figure 2). The lead halide perovskite film remained on the ITO/glass side and was then dissolved in DMF for subsequent lead recycling (inset b in Figure 2). The ITO/glass was washed for reuse for module re-fabrication. No noticeable conductivity changes were observed for the ITO/glass substrate after the recycling process. Even after annealing at 250 °C for 1 hour, the conductivity of the ITO/glass only slightly increased from 14.6 ^/sq to 15.2 ^/sq (inset c in Figure 2). The Cr and Cu electrodes with the encapsulant remained at the back cover glass side, where, after thermal stress, 30 nm of a Cr layer on the top surface turned black and the electrode/encapsulant film formed winkles (inset b in Figure 2). The encapsulant and metal electrode were removed using a knife when the encapsulant was still soft, and then the back cover glass was washed for reuse. Example 3: Lead Removal and Release Experiments The lead removal ratio and lead release ratio of different types of cation exchange resins were investigated in the lead recycling process. It was previously demonstrated that a cation exchange resin layer integrated into the perovskite layer and/or on an electrode can effectively avoid lead leakage when solar modules are broken. ^21,22 In those examples, a strongly acidic cation exchange resin having strong bonding between sulfonic acid and lead displayed excellent lead trapping effects. ^21,22 It was discovered, however, that the preferred choice of lead adsorber for lead recycling is different from previous investigations in lead trapping, as the lead adsorber needs to be able to easily release lead ions. The lead recycling performance of weakly acidic cation (WAC) exchange resins based on both gel and microporous (MP) matrix structures and having a carboxylic acid functional group were compared in Figure 3 with strongly acidic cation (SAC) gel and MP matrix exchange resins having a sulfonic acid functional group. For 10 mL of 4 mM PbI2 (lead concentration of 830 parts per million (ppm)) in DMF, all four types of cation exchange resins removed more than 99.5% of Pb ²⁺ ions from the DMF solution after stirring with 1 g of resin for 20 hours (inset a in Figure 3). When the initial lead concentration was increased to 40 mM (8300 ppm), the WAC-gel maintained a high lead removal ratio of 95%, while the lead removal ratio for the other three cation exchange resins dropped to less than 80% (inset a in Figure 3). For the lead release process using HNO3 regenerant, the carboxylic acid cation exchange resins (WAC-gel and WAC-MP) released most of the adsorbed Pb ²⁺ ions after 30 min of regeneration when the concentration of HNO ₃ regenerant was higher than 0.16 M (inset b in Figure 3). However, the sulfonic acid cation exchange resins SAC-gel and SAC-MP both showed a lower lead release ratio even when the concentration of HNO3 regenerant was up to 2 M (inset b in Figure 3). This low lead release ratio from sulfonic acid cation exchange resins could be attributed to the strong bonding between the sulfonic acid group and Pb ²⁺ ions. In view of the results, the WAC-gel having a carboxylic acid functional group demonstrated the best lead recycling performance for efficient lead removal at high lead concentrations as well as facile lead release from the cation exchange resin. Example 4: Analysis of Lead Adsorption Kinetics The adsorption kinetics of the lead adsorption process on WAC-gel resin are analyzed in the inset (c) in Figure 3. During the rate-limiting step, if the adsorbed ion interacts with a single unoccupied site on the adsorbent, the curve can be fitted with a pseudo-first-order kinetics model: ^42,43 where qe and qt are the amount of lead adsorbed at equilibrium and at time t, respectively (mg/g), and k1 is the rate constant (min ^-1 ). A pseudo-second-order kinetics model is based on sorption equilibrium in which the adsorbed ion interacts with pairs of independent unoccupied sites on the adsorbent during the rate-limiting step. The kinetic rate is: ^42,43 where k2 is the rate constant (min ^-1 ). Figure 3 (inset d) shows how the pseudo-second-order kinetic model more appropriately fits lead adsorption by WAC-gel resin than the pseudo-first-order kinetic model (Figure 6). This indicates that the chemical adsorption of Pb ²⁺ ions involves ion exchanges with two H ⁺ sites on WAC-gel resin during the rate limiting step. Example 5: Investigation of lead Recycling Speed and Efficiency The lead recycling speed and efficiency for high concentration PbI ₂ solution by carboxylic acid cation exchange resins were analyzed. The lead adsorption rate is influenced by the number of available active sites on the resin surface. As such, the adsorption rate decreases when there are fewer active sites. In order to increase the lead removal speed for a high concentration PbI ₂ solution, three treatments were used instead of a single WAC-gel resin treatment. In this three- treatment process, fresh resin was inserted into the PbI2 solution for a second and third treatment following treatment with a first resin. A lead removal ratio of 99.7% could be achieved for a 8300 ppm lead solution after three, WAC-gel treatments (each treatment step was carried out for one hour) (inset e in Figure 3). This three-step treatment significantly decreased the time required for efficient lead removal. It is noted that lead adsorption using iron-incorporated hydroxyapatite as an adsorbent was carried out at an initial PbI ₂ concentration of 2 mM. ³⁷ In comparison, the PbI ₂ concentration in this investigation was 20 times higher. Additionally, the process applied herein resulted in 20-times less required solvent for the recycling process. During lead release, 99.8% of adsorbed lead on WAC-gel resins could be released as soluble Pb(NO ₃ ) ₂ after 10 min of regeneration under 1 M aqueous HNO3 (inset f in Figure 3). Finally, a NaI solution was added to the Pb(NO3)2 solution to convert the soluble Pb(NO3)2 to insoluble PbI2 as a precipitate (Fig.3g) with a conversion ratio of 99.7% (inset h in Figure 3). The overall lead recycling ratio was 99.1% after lead adsorption, lead release, and lead conversion (inset h in Figure 3). Example 6: Lead Recycling with Mixed Cation Perovskite The lead recycling performance of carboxylic acid cation exchange resins for mixed cation perovskites (e.g. perovskites having two cations mixed on the A site) was investigated. The lead removal speeds by WAC-gel for PbI2 solution and a solution containing a mixed cation perovskite (Cs0.1FA0.9PbI3) were compared (inset a in Figure 4). The removal showed similar speeds in both types of solutions. This indicates that the Cs ⁺ ions and FA ⁺ ions did not reduce the lead adsorption rate. It could therefore be reasoned that the cation exchange resin experienced stronger bonding to the Pb ²⁺ ions rather than the other cations in the perovskite solution. For 10 delaminated solar modules having a perovskite composition of Cs _0.1 FA _0.9 PbI ₃ dissolved in 20 mL DMF, the initial lead concentration was 1955 ppm, which dropped to 0.5 ppm with a lead removal ratio of 99.97% after three WAC-gel treatments. For the mixed cation Cs0.1FA0.9PbI3 perovskite solution, after adsorption and desorption ion exchanges and a subsequent reaction with NaI solution, precipitation of pure PbI ₂ without CsI or FAI was confirmed by X-ray diffraction (inset c in Figure 4). Even if the Cs ⁺ ions and FA ⁺ ions were adsorbed and released by the cation exchange resins, CsI and FAI have good solubility in aqueous solution and therefore resist the formation of precipitates. The perovskite solar cells prepared using recycled PbI ₂ and perovskite solar modules prepared using recycled ITO/glass displayed power conversion efficiencies (PCEs) close to devices prepared using fresh commercial raw materials (insets e and d in Figure 4). Example 7: Proposed Recycling Systems During the recycling process, PbI ₂ , front ITO/glass, and back cover glass could be recycled from degraded perovskite solar modules. Moreover, the DMF organic solvent and regenerated cation exchange resin could be reused to reduce costs even further. The regenerated WAC-gel resin demonstrated lead adsorption performance similar to that of fresh resin (inset f in Figure 4). Figure 7A and Figure 7B show that the WAC-gel resin exhibited excellent lead adsorption performance in different organic solvents, aqueous solution, as well as solvents with a wide range of pH values. This allows for easy recovery of lead from fresh and regenerated resins from a wide range of lead-containing solutions. Two proposed lead recycling systems are shown in Figure 5. The systems could use a bath to contain the lead absorbing resin for lead absorption/desorption, or a column for an in-situ process. Example 8: Technoeconomic Assessment A technoeconomic assessment was carried out to analyze the potential cost savings for the perovskite solar module recycling technology described herein. The materials costs were the main costs considered in the assessment. As shown in Table 1, the calculated total material cost for a perovskite solar module based on the structure in inset a of Figure 2 was ~$24.8 /m ² , which is similar to the cost-modeling by Li et al. and Cai et al. ^44,45 The total value of recycled components, including front ITO/glass, PbI2, and back cover glass, was around $12/m ² . Since the perovskite raw material itself only constitutes a small piece of the full perovskite module cost, the recycled PbI2 savings were minor. The recycled ITO glass and cover glass offered the most savings. Rather than consuming materials, the recycling process allows for certain materials—such as DMF, cation exchange resins, HNO ₃ , and NaI—to be reused for multiple cycles. As an example, the following items are needed to recycle a 1 m ² perovskite solar module with a 1 ^m thick lead halide perovskite layer: about 63 g of DMF to prepare a 0.1 M perovskite solution; 20 g resin for three WAC-gel adsorption treatments; 2.7 g of nitric acid for lead release; and 2 g NaI for lead conversion. The material consumption for recycling the perovskite solar module was $4.04 /m ² if the materials are used only once. The material cost could further decrease to $1.14 /m ² if the DMF and resin are each used five times. In addition to the removal of toxic lead from end-of-life perovskite solar modules to avoid environmental pollution, this recycling technique enables dramatic cost savings. Recycled components can provide energy savings compared to the production of new materials. Additionally, the methods described herein provide another source of raw materials that is not dependent on mining, and could also relieve supply chain constraints. Table 1: Cost Estimates Material cost for perovskite solar modules based on 1 µm Cs _0.1 FA _0.9 PbI ₃ film with device structure as shown in the a inset of Fig. 2; recover value of recycled components from perovskite solar modules; and material consumption cost for the proposed recycling process. Note：Sale price from (a) Solaris Chem, (b) Sigma-Aldrich, (c) Greatcell Solar, (d) TCI America, (e) Kurt J. Lesker Company, and (f) ResinTech Inc. Summary In summary, a recycling technology was developed for end-of-life perovskite solar modules that recycles toxic lead from the perovskite films as well as valuable glass components. The technique reduces environmental pollution and enables significant cost savings through regeneration of the materials. The recycling process includes thermal delamination to disassemble modules with intact glass substrates and efficient ion exchange to separate and recycle lead from organic solvents. The carboxylic acid cation exchange resin exhibits a high lead removal ratio to adsorb lead from lead containing solution, as well as a high lead release ratio during resin regeneration to recover lead ions as soluble Pb(NO3)2. The soluble Pb(NO3)2 is then convert to PbI2 for reuse. The methods described herein can recycle both the toxic lead and valuable ITO/glass and back cover glass substrates from decommissioned perovskite solar modules for device re-fabrication. No photovoltaic performance drop was observed for the perovskite solar devices based on recycled PbI2 or recycled ITO/glass compared to fresh counterparts. The cost- effective recycling methods described herein allow for a close-loop lead management system for perovskite solar modules to limit environmental pollution. Materials and Methods Materials. Carboxylic acid cation exchange resin WAC-gel (WACG-HP, gel-type, hydrogen form) and WAC-MP (WACMP, microporous-type, hydrogen form) and sulfonic acid cation exchange resin SAC-MP (SACMP-H, microporous-type, hydrogen form) were purchased from RESINTECH Inc. Sulfonic acid cation exchange resin SAC-gel (AMBERLITE IRC120 H, gel- type, hydrogen form), PTAA (average Mn 7,000–10,000), bathocuproine (BCP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), 2-methoxyethanol (2-ME), toluene, isopropyl alcohol, phenylethyl ammonium chloride, and Pb standard solution (1,000 ± 2 ppm) were purchased from Sigma-Aldrich. Lead(II) iodide (99.99%, trace metals basis, purity: >98.0%) was purchased from TCI America. Formamidinium iodide (FAI) and formamidinium chloride were purchased from GreatCell Solar. C ₆₀ was purchased from Nano-C Inc. Copper (Cu) and chromium (Cr) for thermal evaporation were purchased from Kurt J. Lesker company. Fabrication of perovskite solar cells and modules. Pre-patterned ITO glass substrates (1.5 cm by 1.5 cm for solar cells and 6.5 cm by 8.5 cm for solar modules) were first cleaned by ultrasonication with soap, deionized water, isopropyl alcohol, and acetone, followed by UV ozone treatment for 15 min before use. The PTAA solution with a concentration of 2.2 mg/mL in toluene was blade coated on the ITO/glass substrate at 20 mm/s with 200 µm coating gap. The perovskite film coating was similar to that used in previous investigations. ⁹ The Cs _0.1 FA _0.9 PbI ₃ perovskite films were also blade coated at 20 mm/s with a 250 µm coating gap at room temperature under a nitrogen knife by using a precursor solution containing 1.0 M FAPbI3 and 0.11 M CsPbI3 dissolved in a 2-ME/DMSO solvent mixture. Formamidinium hypophosphite, formamidinium chloride, and phenylethyl ammonium chloride were added into the solution as additives at molar percentages of ~1.0%, ~1.5%, and ~0.15% to Pb ²⁺ ions, respectively. The as-coated solid film was annealed at 150 °C in air for 3 min. Then, the perovskite films underwent thermal evaporation with C ₆₀ (30 nm), BCP (6 nm), and Cu (150 nm) to complete the perovskite solar cell fabrication. For fabricating modules, laser ablation was applied before and after the deposition of the metal electrode (30 nm of Cr and 150 nm of Cu) to complete the series interconnection between sub- cells in the module. Module encapsulation and delamination. Perovskite solar modules were encapsulated by a back cover glass using Gorilla epoxy coated at the top sides of the glass. The modules containing epoxy were then cured for one night. The encapsulant layer thickness after drying was around 300 µm. The module delamination was carried out by placing the encapsulated perovskite solar module on a hot plate at 250 °C for 2 minutes. The encapsulant was softened and melted, and then a knife blade was inserted between the ITO/glass substrate and back cover glass at one corner of the module to detach the two glass substrates. The perovskite layer on the delaminated ITO/glass substrate was dissolved by DMF for the subsequent lead recycling process. Lead recycling test. Various lead sources were used for lead adsorption measurements: PbI ₂ , Cs _0.1 FA _0.9 PbI ₃ , Pb(NO ₃ ) ₂ , and delaminated perovskite solar modules with Cs _0.1 FA _0.9 PbI ₃ perovskite film. The lead adsorption ratios using different cation exchange resins were characterized by measuring the change in the lead concentration of 10 mL 4 mM-40 mM PbI2 solution in DMF after stirring with 1 g cation exchange resin under 400 rpm. For the WAC-gel three treatment procedure, 10 mL of a lead-containing solution was stirred with 1 g WAC-gel under 400 rpm for one hour. Following this, the lead-containing solution was transferred to a second 1g fresh WAC-gel resin for a second hour and then again to a third 1g fresh resin for a third hour. The lead release process was carried out by stirring the lead adsorbed resin with 10 mL of different concentrations of aqueous HNO ₃ at 400 rpm for 30 minutes. A complete lead release process for WAC-gel was carried out using 1M HNO3 for 30 min. After lead release, the regeneration solution together with the released Pb ions were transferred to a precipitation bath, to which 1.5 M NaI aqueous solution was added and after which a yellow PbI ₂ precipitate formed. The PbI2 precipitate was washed by deionized water and isopropyl alcohol and collected by centrifugation, and then dried under vacuum before reuse. The regenerated WAC-gel was rinsed with deionized water before reuse for lead adsorption. The Pb concentration in solution was measured using an ICP-MS Nexion 300D instrument. Before the measurement, the calibration curve for analysis with a lead concentration between 1 part per billion (ppb) and 100 ppb was drawn by measuring standard solutions prepared by mixing the lead standard solution with different amounts of 2% HNO ₃ aqueous solution. For each measurement, the Pb concentration of the tested solution was diluted with 2% HNO3 aqueous solution to 1 ppb and 100 ppb within the linear calibration curve of the ICP-MS. Device characterization. The power conversion efficiency of the perovskite solar cell and solar module were characterized by a J-V measurement under a Xenon lamp–based solar simulator (Oriel Sol3A, Class AAA Solar Simulator). The light intensity was calibrated to 100 mW cm ⁻² with a silicon reference cell (Newport 91150 V-KG5). The J-V curves were measured using a Keithley 2400 source meter with a backward scan rate of 0.1 V s ⁻¹ with a delay time of 10 ms at room temperature. The XRD patterns were obtained using a Rigaku sixth generation MiniFlex X- ray diffractometer. References 1 Jena, A. K., Kulkarni, A. & Miyasaka, T. Halide perovskite photovoltaics: Background, status, and future prospects. Chem. Rev.119, 3036-3103, (2019). 2 Huang, J., Yuan, Y., Shao, Y. & Yan, Y. Understanding the physical properties of hybrid perovskites for photovoltaic applications. Nat. Rev. Mater.2, 17042, (2017). 3 NREL 's Best Research-Cell Efficiency Chart, accessed Jan 4th, 2021. 4 Deng, Y. et al. Tailoring solvent coordination for high-speed, room-temperature blading of perovskite photovoltaic films. Sci. Adv.5, eaax7537, (2019). 5 Subbiah, A. S. et al. High-performance perovskite single-junction and textured perovskite/silicon tandem solar cells via slot-die-coating. ACS Energy Lett.5, 3034-3040, (2020). 6 Das, S. et al. High-performance flexible perovskite solar cells by using a combination of ultrasonic spray-coating and low thermal budget photonic curing. ACS Photonics 2, 680- 686, (2015). 7 Yin, W.-J., Shi, T. & Yan, Y. Unusual defect physics in CH3NH3PbI3 perovskite solar cell absorber. Appl. Phys. Lett.104, 063903, (2014). 8 Li, Z. et al. Scalable fabrication of perovskite solar cells. Nat. Rev. Mater.3, 18017, (2018). 9 Deng, Y. et al. Defect compensation in formamidinium-cesium perovskites for highly efficient and stable solar modules. Nat. Energy, (2021). 10 Extance, A. The reality behind solar power's next star material. Nature 570, 429-433, (2019). 11 Lu, H. Z. et al. Vapor-assisted deposition of highly efficient, stable black-phase FAPbI3 perovskite solar cells. Science 370, eabb8985, (2020). 12 Jeong, J. et al. Pseudo-halide anion engineering for alpha-FAPbI ₃ perovskite solar cells. Nature 592, 381-385, (2021). 13 Jung, E. H. et al. Efficient, stable and scalable perovskite solar cells using poly(3- hexylthiophene). Nature 567, 511-515, (2019). 14 Jiang, Q. et al. Surface passivation of perovskite film for efficient solar cells. Nat. Photonics 13, 460-466, (2019). 15 Chen, S. S., Xiao, X., Gu, H. Y. & Huang, J. S. Iodine reduction for reproducible and high- performance perovskite solar cells and modules. Sci. Adv.7, eabe8130, (2021). 16 Hao, F., Stoumpos, C. C., Cao, D. H., Chang, R. P. H. & Kanatzidis, M. G. Lead-free solid- state organic-inorganic halide perovskite solar cells. Nat. Photonics 8, 489-494, (2014). 17 Jiang, X. Y. et al. Ultra-high open-circuit voltage of tin perovskite solar cells via an electron transporting layer design. Nat. Commun.11, 1245, (2020). 18 Yang, X. Q., Wang, W., Ran, R., Zhou, W. & Shao, Z. P. Recent advances in Cs2AgBiBr6- based halide double perovskites as lead-free and inorganic light absorbers for perovskite solar cells. Energy Fuels 34, 10513-10528, (2020). 19 International Renewable Energy Agency; A Roadmap to 2050, 2019 Edition. 20 Li, X. et al. On-device lead sequestration for perovskite solar cells. Nature 578, 555-558, (2020). 21 Chen, S. et al. Trapping lead in perovskite solar modules with abundant and low-cost cation-exchange resins. Nat. Energy 5, 1003-1011, (2020). 22 Chen, S. et al. Preventing lead leakage with built-in resin layers for sustainable perovskite solar cells. Nat. Sustain., (2021). 23 Heath, G. A. et al. Research and development priorities for silicon photovoltaic module recycling to support a circular economy. Nat. Energy 5, 502-510, (2020). 24 Deng, R., Chang, N. L., Ouyang, Z. & Chong, C. M. A techno-economic review of silicon photovoltaic module recycling. Renew. Sustain. Energy Rev.109, 532-550, (2019). 25 Chowdhury, M. S. et al. An overview of solar photovoltaic panels’ end-of-life material recycling. Energy Strategy Rev.27, 100431, (2020). 26 Liu, F.-W. et al. Recycling and recovery of perovskite solar cells. Mater. Today 43, 185- 197, (2021). 27 Zhang, S. et al. Cyclic utilization of lead in carbon-based perovskite solar cells. ACS Sustain. Chem. Eng.6, 7558-7564, (2018). 28 Kim, B. J. et al. Selective dissolution of halide perovskites as a step towards recycling solar cells. Nat. Commun.7, 11735, (2016). 29 Poll, C. G. et al. Electrochemical recycling of lead from hybrid organic–inorganic perovskites using deep eutectic solvents. Green Chem.18, 2946-2955, (2016). 30 Kadro, J. M. et al. Proof-of-concept for facile perovskite solar cell recycling. Energy Environ. Sci.9, 3172-3179, (2016). 31 Gonzalez, M., Trócoli, R., Pavlovic, I., Barriga, C. & La Mantia, F. Capturing Cd (II) and Pb (II) from contaminated water sources by electro-deposition on hydrotalcite-like compounds. Phys. Chem. Chem. Phys.18, 1838-1845, (2016). 32 Kim, T.-y., Jeung, S.-Y., Cho, S.-Y., Kang, Y. & Kim, S.-J. Removal and regeneration of heavy metal ions using cation exchange column. J Ind. Eng. Chem.10, 695-700, (2004). 33 Goel, J., Kadirvelu, K., Rajagopal, C. & Garg, V. K. Removal of lead (II) by adsorption using treated granular activated carbon: batch and column studies. J. Hazard. Mater.125, 211-220, (2005). 34 Matlock, M. M., Howerton, B. S. & Atwood, D. A. Chemical precipitation of lead from lead battery recycling plant wastewater. Ind. Eng. Chem. Res.41, 1579-1582, (2002). 35 Dean, J. G., Bosqui, F. L. & Lanouette, K. H. Removing heavy metals from waste water. Environ. Sci. Technol.6, 518-522, (1972). 36 Abdullah, N. et al. Polysulfone/hydrous ferric oxide ultrafiltration mixed matrix membrane: preparation, characterization and its adsorptive removal of lead (II) from aqueous solution. Chem. Eng. J.289, 28-37, (2016). 37 Park, S. Y. et al. Sustainable lead management in halide perovskite solar cells. Nat. Sustain. 3, 1044-1051, (2020). 38 Deng, Y. et al. Reduced Self-Doping of Perovskites Induced by Short Annealing for Efficient Solar Modules. Joule 4, 1949-1960, (2020). 39 Shi, L. et al. Gas chromatography-mass spectrometry analyses of encapsulated stable perovskite solar cells. Science 368, 1328, (2020). 40 Cheacharoen, R. et al. Encapsulating perovskite solar cells to withstand damp heat and thermal cycling. Sustain. Energy Fuels 2, 2398-2406, (2018). 41 Jiang, Y. et al. Reduction of lead leakage from damaged lead halide perovskite solar modules using self-healing polymer-based encapsulation. Nat. Energy 4, 585-593, (2019). 42 Fil, B. A., Boncukcuoğlu, R., Yilmaz, A. E. & Bayar, S. Adsorption of Ni (II) on ion exchange resin: Kinetics, equilibrium and thermodynamic studies. Korean J. Chem. Eng. 29, 1232-1238, (2012). 43 Rengaraj, S., Kim, Y., Joo, C. K., Choi, K. & Yi, J. Batch adsorptive removal of copper ions in aqueous solutions by ion exchange resins: 1200H and IRN97H. Korean J. Chem. Eng.21, 187-194, (2004). 44 Li, Z. et al. Cost analysis of perovskite tandem photovoltaics. Joule 2, 1559-1572, (2018). 45 Cai, M. et al. Cost-performance analysis of perovskite solar modules. Adv. Sci.4, 1600269, (2016). 46 Chang, N. L. et al. Manufacturing cost and market potential analysis of demonstrated roll- to-roll perovskite photovoltaic cell processes. Sol. Energy Mater. Sol. Cells 174, 314-324, (2018). 47 Chang, N. L. et al. A manufacturing cost estimation method with uncertainty analysis and its application to perovskite on glass photovoltaic modules. Prog. Photovoltaics 25, 390- 405, (2017). 48 Song, Z. N. et al. A technoeconomic analysis of perovskite solar module manufacturing with low-cost materials and techniques. Energy Environ. Sci.10, 1297-1305, (2017). 49 Horowitz, K. A. et al. An analysis of the cost and performance of photovoltaic systems as a function of module area. (National Renewable Energy Lab, Golden, CO USA, 2017). 50 Louwen, A., Van Sark, W., Schropp, R. & Faaij, A. A cost roadmap for silicon heterojunction solar cells. Sol. Energy Mater. Sol. Cells 147, 295-314, (2016). Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practicing the subject matter described herein. The present disclosure is in no way limited to just the methods and materials described. Throughout this specification and the claims, the words “comprise,” “comprises,” and “comprising” are used in a non-exclusive sense, except where the context requires otherwise. It is understood that embodiments described herein include consisting of and/or consisting essentially of” embodiments. Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limit of the range and any other stated or intervening value in that stated range, is encompassed. The upper and lower limits of these small ranges which may independently be included in the smaller rangers is also encompassed, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included. Many modifications and other embodiments set forth herein will come to mind to one skilled in the art to which this subject matter pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.