Patent Application
20200090876
Tandem solar cells based on dual junctions combining a wide-bandgap (e.g., ˜1.7-1.9 eV) top cell with a narrow-bandgap (e.g., ˜0.9-1.2 eV) bottom cell represent an effective way to push the solar conversion efficiency above the Shockley-Queisser (S-Q) limit (˜31%-33%) for single-junction devices. So far, only III-V compound semiconductors have demonstrated tandem cell efficiencies higher than the S-Q limit. However, the epitaxial growth and expensive substrate has made this technology costly at present. Organic-inorganic metal halide perovskite solar cells (PSCs)—with their rapid efficiency improvement, bandgap tunability, and low-cost processing have become a promising candidate for a variety of tandem devices including perovskite/perovskite, perovskite/CIGS (copper, indium, gallium, selenide), and perovskite/Si. Among these tandem technologies, the polycrystalline thin-film tandem cells (e.g., based on perovskite or CIGS bottom cells) have several potential advantages over the Si-based counterpart such as flexible devices, light weight, and roll-to-roll processing.
The state-of-the-art polycrystalline thin-film CIGS solar cell has a bandgap of ˜1.1 eV and has achieved a certified 22.9% cell efficiency. This makes CIGS a strong candidate as the bottom cell in a tandem configuration to achieve ultrahigh device performance. With the bottom-cell absorber near 1.1 eV, the top cell should ideally have a bandgap near 1.7 eV. In theory, pairing a 1.1-eV bottom cell with a ˜1.7-eV top cell could yield a tandem cell efficiency above 40%. However, there are only a handful of studies on perovskite/CIGS tandem cells, with the best-reported power conversion efficiency (PCE) of 23.9% for a mechanically stacked four-terminal (4-T) configuration and lower efficiency for monolithic two-terminal devices. Thus, a key focus in developing tandem devices is to develop more efficient wide-bandgap PSCs, and methods for the producing such PSCs.
An aspect of the present disclosure is a perovskite that includes A(n−1−nw+w)A′(wn−w)A″2BnX(3n−3zn+3z−4e+1)X′(3zn−3z)X″4e, where each of A, A′, A″ are monovalent cations, B is a divalent cation, each of X, X′, and X″ are monovalent anions, 0<w≤1, 0<z≤1, 0<e≤1, and 1≤n≤100000. In some embodiments of the present disclosure, A″ may include at least one of phenylethyl ammonium (PEA), guanidinium (Gua), butylammonium, cyclopropylammonium, polyethylenimine, iodoethylammonium, ethane-1,2-diammonium, and/or ammoniumvaleric acid. In some embodiments of the present disclosure, X″ may include a pseudohalide. In some embodiments of the present disclosure, X″ may include at least one of thiocyanate (SCN), cyanate, isothiocyanate, azide, selenocyanogen, tellurorhodanide, tetracarbonylcobaltate, and/or AL13I2−.
In some embodiments of the present disclosure, the perovskite may include FA(n−1−nw+w)MA(wn−w)PEA2PbnI(3n−3zn+3z−4e+1)Br(3zn−3z) SCN4e. In some embodiments of the present disclosure, the perovskite may include FA(n−1−nw+w)MA(wn−w)Gua2PbnI(3n−4e+1) SCN4e and z=0. In some embodiments of the present disclosure, the perovskite may include bromine, resulting in FA(n−1−nw+w)MA(wn−w)Gua2PbnI(3n−3zn+3z−4e+1)Br(3zn−3z) SCN4e. In some embodiments of the present disclosure, a perovskite may further include A′″, where A′″ is a monovalent cation, resulting in A(n−nw−nx−1+w+x)A′(wn−w)A″2A′″(xn−x)BnX(3n−3zn+3z−4e+1)X′(3zn−3z)X″4e, where 0<x≤1. In some embodiments of the present disclosure, the perovskite may include FA(n−nw−nx−1+w+x)MA(wn−w)PEA2Cs(xn−x)PbnI(3n−3zn+3z−4e+1)Br(3zn−3z)SCN4e.
In some embodiments of the present disclosure, the perovskite may include FA(n−nw−nx−1+w+x)MA(wn−w)GuA2Cs(xn−x)PbnI(3n−3zn+3z−4e+1)Br(3zn−3z)SCN4e. In some embodiments of the present disclosure, a perovskite may further include B′, where B′ is a monovalent anion, resulting in A(n−nw−nx−1+w+x)A′(wn−w)A″2A′″(xn−x)B(n−ny+y)B(ny−y)X(3n−3zn+3z−4e+1)X′(3zn−3z)X″4e, where 0<y≤1. In some embodiments of the present disclosure, the perovskite may include FA(n−nw−nx−1+w+x)MA(wn−w)PEA2Cs(xn−x)Pb(n−ny+y)B(ny−y)Sn(3n−3zn+3z−4e+1)I(3zn−3z)SCN4e. In some embodiments of the present disclosure, the perovskite may include FA(n−nw−nx−1+w+x)MA(wn−w)Gua2Cs(xn−x)Pb(n−ny+y)B(ny−y)Sn(3n−3zn+3z−4e+1)I(3zn−3z)SCN4e.
In some embodiments of the present disclosure, a perovskite may further include a plurality of grains separated from neighboring grains by a plurality of grain boundaries, where the plurality of grains consist essentially of a first portion of the perovskite, and the plurality of grain boundaries consist essentially of a second portion of the perovskite. In some embodiments of the present disclosure, the first portion may be substantially in a 3D perovskite structure. In some embodiments of the present disclosure, the second portion may be substantially in a 2D perovskite structure. In some embodiments of the present disclosure, each grain may have a characteristic length between 300 nm to 10 μm.
An aspect of the present disclosure is a method that includes completing a first reaction, (1−w)(AX+BX2)+w(A′X′+BX′2)A1−wA′wB(X1−wX′w)3 and completing a second reaction, 2A″X″+(1−e)BX2+eBX″2
A″2B(X2−2eX″2+2e), where the first reaction and the second reaction result in the forming of a perovskite comprising [A1−wA′wB(X1−wX′w)3]n−1[A″2B(X2−2eX″2+2e)]. Each of A, A′, and A″ are monovalent cations, B is a divalent cation, each of X, X′, and X″ are monovalent anions, 0<w≤1, 0<e≤1, and 1≤n≤100000. In some embodiments of the present disclosure, A″ may include at least one of phenylethyl ammonium (PEA), guanidinium (Gua), butylammonium, cyclopropylammonium, polyethylenimine, iodoethylammonium, ethane-1,2-diammonium, and/or ammoniumvaleric acid. In some embodiments of the present disclosure, X″ may include a pseudohalide.
Some embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting.
The present disclosure may address one or more of the problems and deficiencies of the prior art discussed above. However, it is contemplated that some embodiments as disclosed herein may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the embodiments described herein should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.
References in the specification to “one embodiment”, “an embodiment”, “an example embodiment”, “some embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
As used herein the term “substantially” is used to indicate that exact values are not necessarily attainable. By way of example, one of ordinary skill in the art will understand that in some chemical reactions 100% conversion of a reactant is possible, yet unlikely. Most of a reactant may be converted to a product and conversion of the reactant may asymptotically approach 100% conversion. So, although from a practical perspective 100% of the reactant is converted, from a technical perspective, a small and sometimes difficult to define amount remains. For this example of a chemical reactant, that amount may be relatively easily defined by the detection limits of the instrument used to test for it. However, in many cases, this amount may not be easily defined, hence the use of the term “substantially”. In some embodiments of the present invention, the term “substantially” is defined as approaching a specific numeric value or target to within 20%, 15%, 10%, 5%, or within 1% of the value or target. In further embodiments of the present invention, the term “substantially” is defined as approaching a specific numeric value or target to within 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, or 0.1% of the value or target.
As used herein, the term “about” is used to indicate that exact values are not necessarily attainable. Therefore, the term “about” is used to indicate this uncertainty limit. In some embodiments of the present invention, the term “about” is used to indicate an uncertainty limit of less than or equal to ±20%, ±15%, ±10%, ±5%, or ±1% of a specific numeric value or target. In some embodiments of the present invention, the term “about” is used to indicate an uncertainty limit of less than or equal to ±1%, ±0.9%, ±0.8%, ±0.7%, ±0.6%, ±0.5%, ±0.4%, ±0.3%, ±0.2%, or ±0.1% of a specific numeric value or target.
The present disclosure relates to methods for producing perovskite materials having superior performance and/or physical property characteristics. Specifically, the present disclosure relates to methods of making unique perovskites using one or more additives that, among other things, improve the resultant perovskite film quality, crystallinity, lower defect density and energy disorder, increase carrier mobility, and increase carrier mobility. As shown herein, for the example of a (FA0.65MA0.20Cs0.15)Pb(I0.8Br0.2)3 perovskite, the use of two additives, phenylethyl ammonium iodide (PEAT) and lead II thiocyanate (Pb(SCN)2), resulted in a wide bandgap perovskite material (about 1.68 eV) with 20% efficiency, faster carrier mobility (˜47 cm2 V−1s−1) and longer carrier lifetime (˜2.9 μs). When combined with a 1.12 eV CIGS bottom cell, the semi-transparent 1.68 eV perovskite top cell yielded a ˜26.5%-efficient polycrystalline perovskite/CIGS tandem solar cell. This example illustrates the feasibility and advantages that the use of additives may have in manufacturing methods to produce a variety of organic-inorganic perovskite and/or fully inorganic perovskite materials having superior physical property and performance characteristics.
Typical inorganic perovskites include calcium titanium oxide (calcium titanate) minerals such as, for example, CaTiO3 and SrTiO3. In some embodiments of the present invention, the A-cation 110 may include a nitrogen-containing organic compound such as an alkyl ammonium compound. The B-cation 120 may include a metal and the X-anion 130 may include a halogen. Additional examples for the A-cation 110 include organic cations and/or inorganic cations, for example Cs, Rb, K, Na, Li, and/or Fr. Organic A-cations 110 may be an alkyl ammonium cation, for example a C1-20 alkyl ammonium cation, a C1-6 alkyl ammonium cation, a C2-6 alkyl ammonium cation, a C1-5 alkyl ammonium cation, a C1-4 alkyl ammonium cation, a C1-3 alkyl ammonium cation, a C1-2 alkyl ammonium cation, and/or a C1 alkyl ammonium cation. Further examples of organic A-cations 110 include methylammonium (CH3NH3+) (MA), ethylammonium (CH3CH2NH3+), propylammonium (CH3CH2 CH2NH3+), butylammonium (CH3CH2 CH2 CH2NH3+), formamidinium (NH2CH═NH2+) (FA), hydrazinium, acetylammonium, dimethylammonium, imidazolium, guanidinium and/or any other suitable nitrogen-containing or organic compound. In other examples, an A-cation 110 may include an alkylamine. Thus, an A-cation 110 may include an organic component with one or more amine groups. For example, an A-cation 110 may be an alkyl diamine halide such as formamidinium (CH(NH2)2). Thus, the A-cation 110 may include an organic constituent in combination with a nitrogen constituent. In some cases, the organic constituent may be an alkyl group such as straight-chain or branched saturated hydrocarbon group having from 1 to 20 carbon atoms. In some embodiments, an alkyl group may have from 1 to 6 carbon atoms. Examples of alkyl groups include methyl (C1), ethyl (C2), n-propyl (C3), isopropyl (C3), n-butyl (C4), tertbutyl (C4), secbutyl (C4), isobutyl (C4), n-pentyl (C5), 3-pentanyl (C5), amyl (C5), neopentyl (C5), 3-methyl-2-butanyl (C5), tertiary amyl (C5), and n hexyl (C6). Additional examples of alkyl groups include n-heptyl (C7), n-octyl (C8) and the like.
Examples of metal B-cations 120 include, for example, lead, tin, germanium, and or any other 2+ valence state metal that can charge-balance the perovskite 100. Further examples include transition metals in the 2+ state such as Mn, Mg, Zn, Cd, and/or lanthanides such as Eu. B-cations may also include elements in the 3+ valence state, as described below, including for example, Bi, La, and/or Y. Examples for X-anions 130 include halogens: e.g. fluorine, chlorine, bromine, iodine and/or astatine. In some cases, the perovskite may include more than one X-anion 130, for example pairs of halogens; chlorine and iodine, bromine and iodine, and/or any other suitable pairing of halogens. In other cases, the perovskite 100 may include two or more halogens of fluorine, chlorine, bromine, iodine, and/or astatine.
Thus, the A-cation 110, the B-cations 120, and X-anion 130 may be selected within the general formula of ABX3 to produce a wide variety of perovskites 100, including, for example, methylammonium lead triiodide (CH3NH3PbI3), and mixed halide perovskites such as CH3NH3PbI3-xClx and CH3NH3PbI3-xBrx. Thus, a perovskite 100 may have more than one halogen element, where the various halogen elements are present in non-integer quantities; e.g. x is not equal to 1, 2, or 3. In addition, perovskites, like other organic-inorganic perovskites, can form three-dimensional (3-D), two-dimensional (2-D), one-dimensional (1-D) or zero-dimensional (0-D) networks, possessing the same unit structure. As described herein, the A-cation 110 of a perovskite 100, may include one or more A-cations, for example, one or more of cesium, FA, MA, etc. Similarly, the B-cation 120 of a perovskite 100, may include one or more B-cations, for example, one or more of lead, tin, germanium, etc. Similarly, the anion 130 of a perovskite 100 may include one or more anions, for example, one or more halogens. Any combination is possible provided that the charges balance.
For example, a perovskite having the basic crystal structure illustrated in
Further, any perovskite described by the above-mentioned compositions (e.g. ABX3, A2BB′X6, A2BX6, A3B2X9), may include more than one of a given species, A-cation, B-cation, B′-cation, and/or X-anion, provided the charges balance. For example, a perovskite may include more than one A-cation, including a mixture of any of the A-cations listed above; e.g. formamidinium, one or more alkylammonium ions, and/or cesium. Similarly, a perovskite may include one or more X-anions; e.g. one or more halogens fluorine, bromine, chlorine, iodine, etc. Also, a perovskite may have more than one B-cation, for example, more than one of bismuth, silver, and/or copper.
In some embodiments of the present disclosure, a perovskite may have a combination of a three-dimensional (3D) perovskite and a two-dimensional (2D) perovskite.
Referring to Panel B of
Examples of possible A′-cations 210 include phenylethyl ammonium (PEA+), ethylammonium, guanidinium, acetamidinium, [n-, or iso-propylammonium], [n-, iso-, or t-butylammonium], n-butylammonium, [n-, iso-, or neo-pentylammonium], [n-, iso-, or neo-hexylammonium], [n-, iso-, tert- or neo-octylammonium], [n-, iso-, or neo-dodecylammonium], 2-pyrrolidin-1-ium-1-ylethylammonium, 5-azaspiro[4.4]nonan-5-ium, 1,4-benzene diammonium, benzylammonium, butane-1,4-diammonium, N,N-diethylpropane-1,3-diammonium, propane-1,3-diammonium, cyclohexyl ammonium, cyclohexylmethyl ammonium, 1,4-diazabicyclo[2,2,2]octane-1,4-diium, diethylammonium, dimethylammonium, N,N-dimethyl ethane-1,2-diammonium, N,N-dimethylpropane-1,3-di ammonium, ethane-1,2-diammonium, imidazolium, phenethylammonium, phenylammonium, piperazine-1,4-diium, piperidinium, pyridinium, pyrrolidinium, quinuclidin-1-ium, 4-fluoro-phenylammonium, 4-fluoro-benzylammonium, 4-fluoro-phenethylammonium, 4-m ethoxy-phenethylammonium iodide, 4-methoxy-phenylammonium, 4-trifluoromethyl-benzylammonium, and/or 4-trifluoromethyl-phenylammonium. Examples of possible X′-anions 220 include thiocyanate (SCN−), SeCN−, and/or a psuedohalogen. Any of the above cations and/or anions may be provided by a suitable salt; for example, PEA+ may be provided by PEAI, PEABr, PEACl, and/or other anions such as SCN−, etc.
The amount of A′-cation may be defined relative to the amount of A-cation present in the targeted perovskite composition; e.g. ABX3. Specifically, the mole percentage of the A′-cation present in a formulation may be calculated by the total number of moles of A′-cation present in the formulation, divided by the total number of moles of A-cation present in the targeted perovskite, with the fraction then multiplied by 100 to yield the mole percentage of A′-cation present in the formulation. In some embodiments of the present disclosure, the A′-cation may be present at a mole percentage between 0.001% and 50%, or at a mole percentage between 0.001% and 20%. In some embodiments of the present disclosure, the A′-cation may be present a mole percentage between 1% and 5%. The mole percentage of the X′-anion present may be calculated relative to the total amount of the B-cation present in the targeted final perovskite composition; e.g. ABX3. Specifically, the mole percentage of the X′-anion present in a formulation may be calculated by the total number of moles of X′-anion present in the formulation, divided by the total number of moles of X-anion present in the targeted perovskite, with the fraction then multiplied by 100 to yield the mole percentage of X′-anion present in the formulation. In some embodiments of the present disclosure, the X′-anion may be present at a mole percentage between 0.001% and 50%, or at a mole percentage between 0.001% and 20%. In some embodiments of the present disclosure, the X′-anion may be present a mole percentage between 2% and 5%.
In some embodiments of the present disclosure, the methods described herein may be performed under inert conditions (e.g. nitrogen, helium, argon, etc.) or in an air environment. Further, at least one of the combining and/or treating may be performed at a temperature less than 300° C. In some embodiments of the present disclosure, at least one of the combining and/or treating may be performed at a temperature between 25° C. and 300° C.
Next, the method 300 may proceed to the applying 330 of the second solution 327 to a substrate (not shown), resulting in the forming of a liquid film 337 on the substrate. The applying 330 may be accomplished by at least one of spin-coating, curtain coating, dip-coating, blade-coating, slot-die coating, and/or spraying. The resultant liquid film 337 may have a thickness between 100 nm and 5000 nm, inclusively. Possible substrates include ITO, FTO, metal substrates, polyimide, PET, and/or PEN. Some substrates may be flexible. After the applying 330, the liquid film 337 may proceed to a treating 340, e.g. an annealing or thermal treating step, resulting in the formation of the target perovskite 100. Thermal treating may be performed at a temperature between 50° C. and 300° C. In some embodiments of the present disclosure, at least one of the combining 310, the adding 320, and/or the applying 330 may be performed by at least one of a solution processing method, a solid-state processing method, and/or a vapor-phase processing method (e.g. atomic layer deposition (ALD) and/or chemical vapor deposition (CVD).
As described below, the methods and additives described above can result in better performing perovskite materials, resulting in better performing solar cells. For example, an effective additive-engineering approach (described above for
For purposes of illustration and feasibility, the perovskite composition described below was a lead-based mixed-halide (I—Br) and mixed-cation (Cs-MA-FA) perovskite (FA0.65MA0.20Cs0.15)Pb(I0.8Br0.2)3. However, other perovskite compositions can benefit from the methods described herein and fall within the scope of the present disclosure, for example, (FA1−x−yMAxCsy)(Pb1−zSnz)(I1−mBrm)3, where x, y, z, m can each range between 0.0 to 1.0. The perovskite films were prepared by spin coating with a one-step precursor solution in a DMF/NMP mixed solvent. A typical ultraviolet-visible (UV-vis) absorption spectrum of a (FA0.65MA0.20Cs0.15)Pb(I0.8Br0.2)3 perovskite film is shown in
The synergistic effect of using both additives, PEAI and Pb(SCN)2, is evident in the markedly improved device characteristics. Referring to
To understand the effect of PEAI and Pb(SCN)2 on improving device performance in the example perovskite material having 1.68 eV bandgap and a composition of (FA0.65MA0.20Cs0.15)Pb(I0.8Br0.2)3, several structural and optoelectronic characterizations were completed.
One potential issue of using Pb(SCN)2 additive is the formation of excess PbI2. A small amount of excess PbI2 is usually beneficial for PSC operation. However, too much PbI2 is often detrimental to PSC performance.
The excess PbI2 induced by Pb(SCN)2 additive during perovskite formation can be located at/near the grain boundaries (GBs). The suppressed formation of PbI2 when PEAI is added to the perovskite precursor, along with the use of Pb(SCN)2 (see
2A′X+(1−x)BX2+xBX′2→A′2B(X4−2xX′2x) (1a)
2PEAI+(1−x)PbI2+xPb(SCN)2→(PEA)2Pb(I4−2xSCN2x) (1b)
where the form and/or stoichiometry of the final 2D structures may depend on the amount of PEAI, PbI2, Pb(SCN)2, or in other forms with participation from other A-site cations (e.g., MA or FA), and 0≤x≤1. The formation of 2D or quasi-2D perovskites at/near GBs in 3D perovskites can enhance the stability of PSCs based on mixed 3D/2D perovskites. From above, recall that a 2D structure is generally described, with two A cations (e.g. A=FA and A′=PEA+) and one anion (e.g. X′=SCN″), as A′mAn−1BnX′3n+1. When n is equal to 1, the general structure reduces to the 2D structure defined by A′mBX′4, where m=2 for a monovalent A′ and m=1 for a divalent A′. When n>1, the perovskite structure is referred to herein as “quasi-2D”.
Possible reactions that could lead to the formation of 2D or quasi-2D materials as predicted by Reaction (1) above were also evaluated. These were (each first in general form (2a-4a), followed by specific exemplary reactions (2b-4b):
2A′X+BX2→A′2BX4 (2a)
2PEAI+PbI2→(PEA)2PbI4 (2b)
2A′X+BY2→A′2BX2X′2 (3a)
2PEAI+Pb(SCN)2→(PEA)2Pb(I2SCN2) (3b)
2A′Y+BY2→A′2BX′4 (4a)
2PEA(SCN)+Pb(SCN)2→(PEA)2Pb(SCN4). (4b)
2A′X+(n−1)AX+nBX2→A′2An−1BnX3n+1 (5a)
2PEAI+(n−1)MAI+nPbI2→(PEA)2(MA)n−1PbnI3n−1 (5b)
where the layer number n can be adjusted by changing the molar ratios of the precursor components; when n=1, it reduces to Equations 2a and 2b shown above.
Reactions 1a through 5b illustrate that, depending on the ratios of reactants and additives provided in a mixture, not only can the composition of the final perovskite be tailored to a specific composition of interest, but the amount of 2D versus 3D perovskite structures contained in the final perovskite film or layer can also be determined. Thus, in general, some embodiments of the present disclosure describe perovskite solids having both a 3D structure portion, defined by A1−wA′wB1−yB′y(X1−zX′z)3, and a 2D structure portion defined by (A1−cA′c)2B1−dB′d(X1−eX′e)4, where each of w, y, z, c, d, and e are between greater than or equal to zero and less than or equal to one, both A and A′ are monovalent, both B and B′ are divalent, and both X and X′ are monovalent. The ratio of the 2D structure portion to the 3D structure portion contained in the overall perovskite solid (e.g. a film, layer, particle, etc.), and as determined by the relative amounts of the perovskite starting materials (e.g. AX, BX2, A′X, BX′2, A′X′, etc.) may be represented by the following equation:
(n−1)[A1−wA′wB1−yB′y(X1−zX′z)3]+(A1−cA′c)2B1−dB′d(X1−eX′e)4A(n+w−2c−nw+1)A′(nw−w+2c)B(n−ny+y−d)B′(ny−y+d)X(3n−3nz+3z−4e+1)X′(3n−3z+4e) (6)
where, when n equals one, the perovskite is entirely in a 2D structure, and as n gets very large (e.g. approaches infinity, the perovskite is essentially entirely a 3D structure. In between these two extremes, the perovskite is a mixture of both 2D and 3D having the stoichiometry as shown in the product of Reaction 6.
Perovskite GBs (including surfaces) could have various types of structural defects, such as halide vacancies (V1), A-site vacancies (VMA), excess Pb2+, and Pb—I antisite (PbI3−). Due to the ionic nature of perovskites, many of these defects are either positively or negatively charged. In addition to the reduced formation of excess PbI2 arising from the interaction between PEAI and PbI2, it can be hypothesized that the PEA+ cations and SCN− anions could passivate certain charged defects. The lone pair of electrons from sulfur in the S-donor Lewis base (including SCN−) can bind to under-coordinated Pb atoms, which could form via losses of A-site cations and/or halides during annealing. Defects associated with under-coordinated Pb or halide vacancies may be passivated by SCN− located at/near GBs. In addition, PEA+ may fill in A-site vacancies (e.g., VMA) during perovskite preparation and the thermal annealing process. Thus, defects associated with A-site vacancies are also expected to be reduced.
Without wishing to be bound by theory, one defect passivation mechanism suggests that both PEA+ and SCN− can be primarily located at/near the GBs. To check this hypothesis, time-of-flight secondary-ion mass spectrometry (TOF-SIMS) tomography was used to study the exemplary (FA0.65MA0.20Cs0.15)Pb(I0.8Br0.2)3 perovskite thin film prepared by using both 1 mol % PEAI and 2 mol % Pb(SCN)2 additives in the perovskite precursor. TOF-SIMS is one of the few characterization techniques that can provide chemical information with a spatial resolution of up to about 100 nm.
The effect of using PEAI and Pb(SCN)2 additives on charge-carrier transport and lifetime were also evaluated by time-resolved microwave conductivity (TRMC) measurement. TRMC is a contactless technique that has been used to study charge-carrier dynamics in perovskite thin films.
Referring to
Semi-transparent PSCs were developed in order to construct perovskite/CIGS tandem solar cells in a 4-terminal configuration. The device stack constructed using the semi-transparent PSC was glass/ITO/PTAA/perovskite/C60/SnOx/Zn:SnOx(ZTO)/IZO. A thin 6-nm SnOx layer followed by an ˜1-nm ZTO layer was deposited by atomic layer deposition, whereas ˜250 nm of IZO was deposited by sputtering. The J-V curve for the semi-transparent PSC is shown in
Finally, Table 3 illustrates characteristics for the perovskite solar cells illustrated
In summary, an effective solution chemistry is demonstrated herein to prepare highly efficient wide-bandgap (1.68-eV) PSCs by incorporating both PEA+ and SCN− to form a 3D perovskite structure containing 2D (or quasi-2D) structures located primarily at/near grain boundaries. The coupling of PEA+ (from PEAI) and SCN− (from Pb(SCN)2) overcomes the separate challenges associated with each additive, leading to enhanced perovskite crystallinity and reduced PbI2 formation along with reduced defect density and energy disorder. As a result, the charge-carrier mobility and lifetime increase from <10 cm2 V−1s−1 and <1 μs for the control sample to near 50 cm2 V−1s−1 and 3 μs by using both additives. The average PSC performance increases from 16.3% to 18.7%, with optimized cell efficiency of ˜20%. When semi-transparent PSC with an IZO top contact were coupled with a 1.12-eV CIGS bottom cell, ˜26.5% perovskite/CIGS 4-terminal thin-film tandem solar cells resulted. These results demonstrate the feasibility of PSC enabling >30% all-thin-film tandem devices with a CIGS bottom cell.
In addition, low-bandgap perovskite films were also prepared. In one embodiment of the present disclosure, an (FASnI3)0.6(MAPbI3)0.4 precursor was prepared by mixing formamidinium iodide (FAI) (Dyesol, 0.6 mmol), SnI2 (Alfa, 0.6 mmol), SnF2 (Sigma-Aldrich, 0.06 mmol), CH3NH3I (MAI) (Dyesol, 0.4 mmol), PbI2 (Alfa, 0.4 mmol) in 800 μL N,N-dimethylmethanamide (DMF) (anhydrous, Sigma-Aldrich) and 200 μL dimethyl sulfoxide (DMSO) (anhydrous, Sigma-Aldrich). In some examples, the perovskite formulation was modified by the addition of guanidinium thiocyanate (GuaSCN) as an additive. GuaSCN powder (Sigma-Aldrich) was directly added to the low-bandgap perovskite powders in different molar ratios. Different thicknesses of the resultant perovskite films were realized by changing the precursor concentration. For perovskite precursors with high concentrations, thermal annealing at 65° C. for about 30 minutes was applied to assist dissolving the precursors. The perovskite precursors with different molar concentrations were spin-coated onto the ITO/PEDOT:PSS substrate at 5000 rpm for 30 seconds. During the spin-coating, 400 μL of toluene was dropped onto the spinning substrates. The resulting perovskite films were then annealed at 100° C. for 10 min to form (FASnI3)0.6(MAPbI3)0.4 or GuaSCN-modified (FASnI3)0.6(MAPbI3)0.4 perovskite thin films.
Thus, in some embodiments of the present disclosure, a perovskite containing a 3D structure and a 2D structure may be produced by using a single additive, GauSCN, according to the following reaction:
2GuaSCN+PbI2→(Gua)2Pb(I2SCN2) (7a)
Reaction (7a) may be written generally as,
2A′Y+BX2→A′2BX2X′2 (7b)
which is equivalent to Reaction (3a) above.
This example using GauSCN as an additive in the perovskite formulation, further demonstrates an additive-engineering approach to prepare >20%-efficient low-bandgap (˜1.25 eV) perovskite solar cell based on Sn—Pb mixed perovskite absorbers ((FASnI3)0.6(MAPbI3)0.4). The use of GuaSCN as an additive improves perovskite film quality with enhanced crystallinity, larger grain size, smoother grain surface, longer carrier lifetime, reduced energy disorder, faster carrier transport, and longer carrier diffusion length (˜2.5 micrometer). These improved perovskite properties resulted in an improved average solar cell efficiency from <16% to >18%. When increasing the perovskite film thickness to about 1 micrometer, the solar cell efficiency reached about 20.2%-20.4% owing to the significantly improved carrier diffusion length; this efficiency level is much higher than the state-of-the-art (˜17%-18%) reported in literature. Coupling a semi-transparent 1.63-eV perovskite top cell with a 1.25-eV perovskite bottom cell, a ˜25%-efficient polycrystalline perovskite/perovskite 4-terminal thin-film tandem solar cell was achieved.
Materials.
Unless stated otherwise, all materials were purchased from Sigma-Aldrich, Alfa Aesar, TCI, or Greatcellsolar and were used as received. C60 was purchased from Lumtec and used as received.
Preparation of Perovskite Precursor.
The precursor of 3D perovskite (FA0.65MA0.20Cs0.15)Pb(I0.8Br0.2)3 film was prepared by dissolving FAI, CsI, MABr, PbI2, and PbBr2 with stoichiometry in anhydrous N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP) mixed solvent (4/1, v/v). The molar concentration of the perovskite precursor was in the range of 1M to 1.5M. To obtain 2D/3D mixed perovskite, FAI in precursor was substituted by PEAI, with the desired molar concentration ranging from 0 to 3 mol %. The Pb(SCN)2 additive was used for both 3D and 2D/3D perovskite precursors with concentration varying from 0 to 5 mol %, calculated based on Pb amount. Perovskite precursors were stirred at room temperature for 3 hours before perovskite film deposition. Perovskite precursor solution concentration and spin-coating speed were adjusted for device optimization.
Perovskite Solar Cell Fabrication.
The PTAA solution dissolved in toluene (5 mg/l mL) was spin-coated on the cleaned ITO substrate at 6,000 rpm for 25 seconds followed by annealing at 100° C. for 10 min in N2-filled glovebox. After annealing, the PTAA/ITO substrate was further spin-coated with DMF to improve the wettability of perovskite precursor. 60 μL of perovskite precursor was coated on the DMF pre-treated PTAA/ITO substrate at a spin speed of 4,000 rpm for 25 seconds to form a solid-state-precursor (SSP) film. The SSP film was subsequently immersed into diethyl ether bath for about 30 seconds to 60 seconds. The color of the SSP film immediately changed from transparent to brown during solvent extraction. The substrate was then sequentially annealed at 65° C. for 10 min and 100° C. for 13 minutes. For devices with an opaque top contact, the perovskite film was sequentially coated with about 30-nm C60, 6-nm BCP, and 100-nm Ag by thermal evaporation. For devices with a transparent top contact, the perovskite film was first coated with about 30-nm C60 by thermal evaporation, and followed by coating of about 6-nm SnOx and 1-nm of Zn-doped SnOx (ZTO) layers by atomic layer deposition (ALD). Finally, about 250 nm of IZO layer were sputtered at room-temperature using an RF power of 100 W in a vacuum chamber with a base pressure of 2×10−7 torr. The sheet resistance of a thin film of IZO deposited on glass with identical deposition parameters was measured to be about 12 Ω/sq. using a four-point probe.
CIGS Cell Fabrication.
A 0.5-μm Mo back contact was sputtered onto aluminosilicate glass that had high K content (Etamax purchased from Schott). A bandgap-graded, 2.5-μm-thick Cu(In,Ga)Se2 absorber layer was then grown by 3-stage co-evaporation at 615° C. A post-deposition treatment was performed after cooling the absorber to 330° C. and evaporating 25 nm of KF over 10 min (no Se supplied). The overall film had cation molar ratios of Cu/(Ga+In) of 0.89 and Ga/(Ga+In) of 0.34 by X-ray fluorescence, and a bandgap of 1.12 eV. The device was completed with an n-type buffer layer (50-nm CdS by chemical bath deposition), intrinsic buffer (90-nm sputtered ZnO), doped window (120-nm sputtered Al-doped ZnO), metal grids (Ni/Al evaporated through a shadow mask), and anti-reflective coating (100-nm evaporated MgF2). Devices with 0.42 cm2 area were isolated by photolithography and hydrochloric acid etching.
ALD Coating of Tin Oxide and Zinc-Tin-Oxide.
The tin oxide (SnOx) and zinc-tin-oxide (ZTO) processes were deposited using a Beneq TFS200 ALD system at 85° C. using tetrakis(dimethylamino)tin(IV) (TDMASn), diethylzinc (DEZ), and water. Chamber and process nitrogen flows were set to 250 and 300 sccm, respectively. TDMASn was heated to 55° C.; DEZ and water were unheated. TDMASn was pulsed using a bubbler charge-pulse-purge procedure, where the bubbler was charged with nitrogen for 0.35 seconds, pulsed for 1 seconds, then pulsed for an additional 0.2 seconds with nitrogen flow through the bubbler. The SnOx deposition cycle consisted of the processing sequence: TDMASn charge-pulse-purge procedure, purge (6 seconds), H2O pulse (0.2 seconds), purge (6 seconds). This process resulted in a growth of 1.4 Å/cycle. ZTO was deposited using a supercycle approach, in which a single supercycle consisted of 3 cycles of zinc oxide (ZnO) followed by 3 cycles of SnOx. The ZnO deposition cycle consisted of a DEZ pulse (0.2 seconds), purge (6 seconds), H2O pulse (0.2 seconds), purge (6 seconds). This ZTO supercycle process resulted in a growth rate of 10 Å/supercycle.
Material Characterization.
The crystal structures of perovskite films were characterized using an X-ray diffractometer (XRD, D-Max 2200, Rigaku). The morphologies and microstructures of perovskite films and the cross-sectional structure of solar cells were examined by using a field-emission scanning electron microscopy (FESEM, Nova 630 NanoSEM, FEI). The optical absorption spectra of perovskite films were characterized using a UV-Vis spectrophotometer (Cary-6000i, Agilent).
Time-of-Flight Secondary-Ion Mass Spectrometry.
An ION-TOF TOF-SIMS V Time of Flight SIMS (TOF-SIMS) spectrometer was used for depth profiling and chemical imaging of the perovskite. Analysis was completed using a 3-lens 30-kV BiMn primary-ion gun. 1D profiles were completed with the Bi3+ primary-ion beam, (0.8-pA pulsed beam current), and a 50×50-μm area was analyzed with a 128:128 primary beam raster. 3-D tomography was completed with 100-nm lateral resolution using a Bi3++ primary-ion-beam cluster (100-ns pulse width, 0.1-pA pulsed beam current); a 50×50-μm area was sampled with a 1024:1024 primary-beam raster. Sputter depth profiling was accomplished with 1-kV oxygen and cesium ion sputter beams (3-5-nA sputter current) with a raster of 1×150 μm. After completion of the SIMS measurements, the depth of the craters was determined by optical interference light microscopy to convert the SIMS sputter time scale to a sputter depth scale.
Time-Resolved Microwave Conductivity.
Thin-film perovskite samples deposited on quartz substrates (1 cm×2.5 cm×1 mm) were illuminated through the quartz side of the substrate with 650-nm (5-ns pulse width) laser using an optical parametric oscillator (Continuum Panther) pumped by the 355-nm harmonic of a Q-switched Nd:YAG laser (Continuum Powerlite). The transient change in photoconductance (ΔG(t)) was measured via changes in the microwave power (ΔP(t)) due to absorption of microwaves (˜9 GHz) by the photogenerated holes and electrons, and it is given by:
ΔG(t)=(−1/K)(ΔP(t)/P), (7)
where K is a calibration factor experimentally determined from the resonance characteristics of the microwave cavity and the dielectric properties of the sample. The end-of-pulse (peak) photoconductance (ΔGpeak) can be related to the product of the yield of free-carrier generation (p) and the sum (Σμ) of the GHz-frequency mobilities of electron (μe) and hole (μh) by:
ΔGpeak=βqeN(μe+μh)=βqeI0FAφΣμ, (8)
where β=2.2 and is the ratio of the interior dimensions of the waveguide, qe is the electronic charge, N is the number of photogenerated charge-carrier pairs, I0 is the incident photon flux of the excitation laser pulse, and FA is the fraction of photons absorbed by the sample. In bulk semiconductors, where the photogeneration yield can be assumed to be unity, the photoconductance provides a measure of the carrier mobility. Transient photoconductance data were recorded at pump excitation intensities (˜1-sun) where recombination and peak photoconductance is independent of intensity, provided sufficient signal-to-noise was attainable.
Device Characterization.
The photocurrent densityvoltage (J-V) curves were measured under a simulated AM 1.5G illumination (100 mW cm−2, Oriel Sol3A Class AAA Solar Simulator, Newport) and nitrogen condition in a glove box using a Keithley 2400 source meter with 20-mV steps and 60-ms delay time. The AM 1.5G illumination was calibrated using a standard Si solar cell (Oriel, VLSI standards) and KG2 filter. The stabilized power output (SPO) of PSCs was also measured using the same equipment. The active area of PSCs was 0.06 cm2 as determined by the black metal aperture. External quantum efficiency (EQE) spectra of devices were measured using a solar cell quantum-efficiency measurement system.
For perovskite/CIGS 4-T tandem devices, the J-V curves and EQE spectra of semi-transparent perovskite top cells were measured using the same condition as described above. The filtered CIGS cell with an active area of ˜0.4 cm2 was measured by using a large-area (˜0.6-cm2) semi-transparent perovskite device filter with IZO top contact under a simulated AM 1.5G illumination (100 mW cm−2, Oriel Sol3A Class AAA Solar Simulator, Newport) at ambient condition. Paraffin oil (refractive index of ˜1.47) was used as an optical coupler to remove the air gap between the top perovskite device filter and the bottom CIGS cell.
A perovskite comprising: a first portion comprising A1−wA′wB(X1−zX′z)3, and a second portion comprising A″2B(X1−eX″e)4, wherein: each of A, A′, A″ are monovalent cations, B is a divalent cation, each of X, X′, and X″ are monovalent anions, 0≤w≤1, 0≤z≤1, and 0≤e≤1.
The perovskite of Example 1, wherein the first portion and the second portion are at a ratio of the second portion to the first portion of 1/(n−1), and 1≤n≤100000.
The perovskite of Example 2, wherein 1≤n≤10000.
The perovskite of Example 3, wherein 1≤n≤1000.
The perovskite of Example 4, wherein 1≤n≤100.
The perovskite of Example 1, wherein the second portion is present in the perovskite at a molar concentration between greater than 0% and less than or equal to 50%.
The perovskite of Example 6, wherein the second portion is present in the perovskite at a molar concentration between greater than 0% and less than or equal to 20%.
The perovskite of Example 1, wherein A comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The perovskite of Example 1, wherein A′ comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The perovskite of Example 1, wherein A″ comprises at least one of phenylethyl ammonium (PEA), guanidinium (Gua), butylammonium, cyclopropylammonium, polyethylenimine, iodoethylammonium, ethane-1,2-diammonium, or ammoniumvaleric acid.
The perovskite of Example 1, wherein B comprises at least one of lead, tin, or germanium.
The perovskite of Example 1, wherein X comprises a halide.
The perovskite of Example 1, wherein X′ comprises a halide.
The perovskite of Example 1, wherein X″ comprises a pseudohalide.
The perovskite of Example 1, wherein X″ comprises at least one of thiocyanate (SCN), cyanate, isothiocyanate, azide, selenocyanogen, nitrite, tellurorhodanide, tetracarbonylcobaltate, or AL13I2−.
The perovskite of Example 1, wherein: the first portion comprises FA1−wMAwPb(I1−zBrz)3, 0<w≤1, and 0<z≤1.
The perovskite of Example 16, wherein 0<w≤0.8 and 0.05<z≤0.4.
The perovskite of Example 1, wherein: the second portion comprises PEA2Pb(I1−eSCNe)4, and 0<e≤1.0.
The perovskite of Example 18, wherein 0.20≤e≤0.4.
The perovskite of Example 1, wherein: the second portion comprises Gua2Pb(I1−eSCNe)4, and 0<e≤1.0.
The perovskite of Example 20, wherein 0.20≤e≤0.4.
The perovskite of Example 1, wherein: the first portion further comprises A′″ resulting in A1−w−xA′wA′″xB(X1−zX′z)3, A′″ is a monovalent cation, and 0<x≤1.
The perovskite of Example 22, wherein A′″ comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The perovskite of Example 16, further comprising: cesium such that the first portion comprises FA1−w−xMAwCsxPb(I1−zBrz)3, wherein: 0<x≤1.
The perovskite of Example 24, wherein 0.01<x≤0.3.
The perovskite of Example 22, wherein: the first portion further comprises B′ resulting in A1−w−xA′wA′″xB1−yB′y(X1−zX′z)3, B′ is a divalent cation, and 0<y≤1.
The perovskite of Example 26, wherein B′ comprises at least one of lead, tin, or germanium.
The perovskite of Example 16, further comprising: tin such that the first portion comprises FA1−wMAwSn1−yPbyI3, 0<w≤1, 0<y≤1, and z=0.
The perovskite of Example 28, wherein 0.5≤w≤0.8, and 0.2≤y≤0.6.
The perovskite of Example 1, further comprising: a plurality of grains separated from neighboring grains by a plurality of grain boundaries, wherein: the plurality of grains consist essentially of the first portion, and the plurality of grain boundaries consist essentially of the second portion.
The perovskite of Example 30, wherein each grain has a characteristic length between 300 nm to 10 μm.
A perovskite comprising: A(n−1−nw+w)A′(wn−w)A″2BnX(3n−3zn+3z−4e+1)X′(3zn−3z)X″4e, wherein: each of A, A′, A″ are monovalent cations, B is a divalent cation, each of X, X′, and X″ are monovalent anions, 0<w≤1, 0<z≤1, 0<e≤1, and 1≤n≤100000.
The perovskite of Example 1, wherein 1≤n≤10000.
The perovskite of Example 2, wherein 1≤n≤1000.
The perovskite of Example 3, wherein 1≤n≤100.
The perovskite of Example 1, wherein the second portion is present in the perovskite at a molar concentration between greater than 0% and less than or equal to 50%.
The perovskite of Example 5, wherein the second portion is present in the perovskite at a molar concentration between greater than 0% and less than or equal to 20%.
The perovskite of Example 1, wherein A comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The perovskite of Example 1, wherein A′ comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The perovskite of Example 1, wherein A″ comprises at least one of phenylethyl ammonium (PEA), guanidinium (Gua), butylammonium, cyclopropylammonium, polyethylenimine, iodoethylammonium, ethane-1,2-diammonium, or ammoniumvaleric acid.
The perovskite of Example 1, wherein B comprises at least one of lead, tin, or germanium.
The perovskite of Example 1, wherein X comprises a halide.
The perovskite of Example 1, wherein X′ comprises a halide.
The perovskite of Example 1, wherein X″ comprises a pseudohalide.
The perovskite of Example 1, wherein X″ comprises at least one of thiocyanate (SCN), cyanate, isothiocyanate, azide, selenocyanogen, tellurorhodanide, tetracarbonylcobltate, or AL13I2−.
The perovskite of Example 1, comprising FA(n−1−nw+w)MA(wn−w)PEA2PbnI(3n−3zn+3z−4e+1)Br(3zn−3z)SCN4e.
The perovskite of Example 15, wherein 0<w≤0.8, 0.05<z≤0.4, and 0<e≤1.0.
The perovskite of Example 1 comprising FA(n−1−nw+w)MA(wn−w)GUa2PbnI(3n−4e+1) SCN4e and z=0.
The perovskite of Example 17, wherein 0<w≤0.8 and 0<e≤1.0.
The perovskite of Example 17, further comprising bromine, resulting in
FA(n−1−nw+w)MA(wn−w)GUa2PbnI(3n−3zn+3z−4e+1)Br(3zn−3z)SCN4e.
The perovskite of Example 19, wherein 0.05≤z≤0.4.
The perovskite of Example 1, further comprising A′″, wherein: A′″ is a monovalent cation, resulting in A(n−nw−nx−1+w+x)A(wn−w)A″2A′″(xn−x)BnX(3n−3zn+3z−4e+1)X′(3zn−3z)X″4e, and 0<x≤1.
The perovskite of Example 21, wherein A′″ comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The perovskite of Example 21, comprising: FA(n−nw−nx−1+w+x)MA(wn−w)PEA2Cs(xn−x)PbnI(3n−3zn+3z−4e+1)Br(3zn−3z)SCN4e.
The perovskite of Example 23, wherein 0.01≤x≤0.3.
The perovskite of Example 21, comprising FA(n−nw−nx−1+w+x)MA(wn−w)Gua2Cs(xn−x)PbnI(3n−3zn+3z−4e+1)Br(3zn−3z)SCN4e.
The perovskite of Example 25, wherein 0.01≤x≤0.3.
The perovskite of Example 21, further comprising B′, wherein: B′ is a monovalent anion, resulting in A(n−nw−nx−1+w+x)A′(wn−w)A″2A′″(xn−x)B(n−ny+y)B(ny−y)X(3n−3zn+3z−4e+1)X′(3zn−3z)X″4e, and 0<y≤1.
The perovskite of Example 27, wherein B′ comprises at least one of lead, tin, or germanium.
The perovskite of Example 27, comprising: FA(n−nw−nx−1+w+x)MA(wn−w)PEA2Cs(xn−x)Pb(n−ny+y)Sn(3n−3zn+3z−4e+1)I(3zn−3z)SCN4e.
The perovskite of Example 29, wherein 0.2≤y≤0.6.
The perovskite of Example 27, comprising: FA(n−nw−nx−1+w+x)MA(wn−w)Gua2Cs(xn−x)Pb(n−ny+y)Sn(3n−3zn+3z−4e+1)I(3zn−3z)SCN4e.
The perovskite of Example 31, wherein 0.2≤y≤0.6.
The perovskite of Example 1, further comprising: a plurality of grains separated from neighboring grains by a plurality of grain boundaries, wherein: the plurality of grains consist essentially of a first portion of the perovskite, and the plurality of grain boundaries consist essentially of a second portion of the perovskite.
The perovskite of Example 33, wherein the first portion is substantially in a 3D perovskite structure.
The perovskite of Example 33, wherein the second portion is substantially in a 2D perovskite structure.
The perovskite of Example 33, wherein each grain has a characteristic length between 300 nm to 10 μm.
A method comprising: completing a first reaction, (1−w)(AX+BX2)+w(A′X′+BX′2)A1−wA′wB(X1−wX′w)3; and completing a second reaction, 2A″X″+(1−e)BX2+eBX″2
A″2B(X2−2eX″2+2e), wherein: the first reaction and the second reaction result in the forming of a perovskite comprising [A1−wA∝wB(X1−wX′w)3]n−1[A″2B(X2−2eX″2+2e)], each of A, A′, and A″ are monovalent cations, B is a divalent cation, each of X, X′, and X″ are monovalent anions, 0<w≤1, 0<e≤1, and 1≤n≤100000.
The method of Example 1, wherein 1≤n≤10000.
The method of Example 2, wherein 1≤n≤1000.
The method of Example 3, wherein 1≤n≤100.
The method of Example 1, wherein the A″2B(X2−2eX″2+2e) is present in the perovskite at a molar concentration between greater than 0% and less than or equal to 50%.
The method of Example 5, wherein the A″2B(X2−2eX″2+2e) is present in the perovskite at a molar concentration between greater than 0% and less than or equal to 20%.
The method of Example 1, wherein A comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The method of Example 1, wherein A′ comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The method of Example 1, wherein A″ comprises at least one of phenylethyl ammonium (PEA), guanidinium (Gua), butylammonium, cyclopropylammonium, polyethylenimine, iodoethylammonium, ethane-1,2-diammonium, or ammoniumvaleric acid.
The method of Example 1, wherein B comprises at least one of lead, tin, or germanium.
The method of Example 1, wherein X comprises a halide.
The method of Example 1, wherein X′ comprises a halide.
The method of Example 1, wherein X″ comprises a pseudohalide.
The method of Example 1, wherein X″ comprises at least one of thiocyanate (SCN), cyanate, isothiocyanate, azide, selenocyanogen, tellurorhodanide, tetracarbonylcobaltate, or AL13I2−.
The method of Example 1, wherein A1−wA′wB(X1−wX′w)3 comprises FA1−wMAwPb(I1−wBrw)3.
The method of Example 15, wherein 0.05<w≤0.8.
The method of Example 1, wherein A″2B(X2−2eX″2+2e) comprises PEA2Pb(I2−2eSCN2+2e).
The method of Example 17, wherein 0.1≤e≤0.9.
The method of Example 1, wherein A″2B(X2−2eX″2+2e) comprises Gua2Pb(I2−2eSCN2+2e).
The method of Example 19, wherein 0.1≤e≤0.9.
The method of Example 1, wherein: the first reaction further comprises, (1−w−x)(AX+BX2)+w(A′X′+BX′2)+x(A′″X+BX2)A1−w−xA′wA′″xB(X3−3wX′w+2w), wherein: A′″ is a monovalent cation, and 0<x≤1.
The method of Example 21, wherein A′″ comprises at least one of cesium, formamidinium (FA), methylammonium (MA), rubidium, potassium, or sodium.
The method of Example 21, wherein A1−w−xA′wA′″xB(X3−3wX′w+2w) comprises
FA1−w−xMAwCsxPb(I3−3wBrw+2w).
The method of Example 23, wherein 0.01≤x≤0.3.
The method of Example 21, wherein: the first reaction further comprises, (1−w−x−y)(AX+BX2)+w(A′X′+BX′2)+x(A′″X+BX2)+y(AX+B′X2)A1−w−xA′wA′″xB1−yB′y(X3−3wX′w+2w), wherein: B′ is a divalent cation, and 0<y≤1.
The method of Example 25, wherein B′ comprises at least one of lead, tin, or germanium.
The method of Example 25, wherein A1−w−xA′wA′″xB1−yB′y(X3−3wX′w+2w) comprises
FA1−w−xMAwCsxPb1−ySny(I3−3wBrw+2w).
The method of Example 27 wherein 0.2<y≤0.6.
The method of Example 1, wherein the completing of the first reaction and the completing of the second reaction are performed in a liquid phase.
The method of Example 29, wherein the liquid phase includes a polar solvent.
The method of Example 30, wherein the polar solvent comprises N,N-dimethylformamide.
The method of Example 31, wherein the polar solvent further comprises N,N-dimethylformamide.
The method of Example 29, wherein, before the completing of first reaction, each of AX, BX2, A′X′, BX′2 are at a concentration in the liquid phase between 0.1M and 10M.
The method of Example 29, wherein, before the completing of first reaction, each of AX, BX2, A′X′, BX′2 are at a concentration in the liquid phase between 1M and 1.5M.
The method of Example 29, wherein, before the completing of second reaction, each of A″X and BX″2 are at a concentration in the liquid phase between greater than 0 mol % and 50 mol %.
The method of Example 29, wherein, before the completing of second reaction, each of A″X and BX″2 are at a concentration in the liquid phase between greater than 0 mol % and 20 mol %.
The foregoing discussion and examples have been presented for purposes of illustration and description. The foregoing is not intended to limit the aspects, embodiments, or configurations to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the aspects, embodiments, or configurations are grouped together in one or more embodiments, configurations, or aspects for the purpose of streamlining the disclosure. The features of the aspects, embodiments, or configurations, may be combined in alternate aspects, embodiments, or configurations other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the aspects, embodiments, or configurations require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment, configuration, or aspect. While certain aspects of conventional technology have been discussed to facilitate disclosure of some embodiments of the present invention, the Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate aspect, embodiment, or configuration.
This application claims the benefit of U.S. Provisional Patent Application No. 62/731,413 filed Sep. 14, 2018, the contents of which are incorporated herein by reference in their entirety.
The United States Government has rights in this disclosure under Contract No. DE-AC36-08GO28308 between the United States Department of Energy and Alliance for Sustainable Energy, LLC, the Manager and Operator of the National Renewable Energy Laboratory.
| Number | Date | Country | |
|---|---|---|---|
| 62731413 | Sep 2018 | US |
