1
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Connor BA, Su AC, Slavney AH, Leppert L, Karunadasa HI. Understanding the evolution of double perovskite band structure upon dimensional reduction. Chem Sci 2023; 14:11858-11871. [PMID: 37920347 PMCID: PMC10619643 DOI: 10.1039/d3sc03105e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 09/10/2023] [Indexed: 11/04/2023] Open
Abstract
Recent investigations into the effects of dimensional reduction on halide double perovskites have revealed an intriguing change in band structure when the three-dimensional (3D) perovskite is reduced to a two-dimensional (2D) perovskite with inorganic sheets of monolayer thickness (n = 1). The indirect bandgap of 3D Cs2AgBiBr6 becomes direct in the n = 1 perovskite whereas the direct bandgap of 3D Cs2AgTlBr6 becomes indirect at the n = 1 limit. Here, we apply a linear combination of atomic orbitals approach to uncover the orbital basis for this bandgap symmetry transition with dimensional reduction. We adapt our previously established method for predicting band structures of 3D double perovskites for application to their 2D congeners, emphasizing new considerations required for the 2D lattice. In particular, we consider the inequivalence of the terminal and bridging halides and the consequences of applying translational symmetry only along two dimensions. The valence and conduction bands of the layered perovskites can be derived from symmetry adapted linear combinations of halide p orbitals propagated across the 2D lattice. The dispersion of each band is then determined by the bonding and antibonding interactions of the metal and halide orbitals, thus affording predictions of the essential features of the band structure. We demonstrate this analysis for 2D Ag-Bi and Ag-Tl perovskites with sheets of mono- and bilayer thickness, establishing a detailed understanding of their band structures, which enables us to identify the key factors that drive the bandgap symmetry transitions observed at the n = 1 limit. Importantly, these insights also allow us to make the general prediction that direct → indirect or indirect → direct bandgap transitions in the monolayer limit are most likely in double perovskite compositions that involve participation of metal d orbitals at the band edges or that have no metal-orbital contributions to the valence band, laying the groundwork for the targeted realization of this phenomenon.
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Affiliation(s)
- Bridget A Connor
- Department of Chemistry, Stanford University Stanford CA 94305 USA
| | - Alexander C Su
- Department of Chemistry, Stanford University Stanford CA 94305 USA
| | - Adam H Slavney
- Department of Chemistry, Stanford University Stanford CA 94305 USA
| | - Linn Leppert
- MESA+ Institute for Nanotechnology, University of Twente 7500 AE Enschede The Netherlands
| | - Hemamala I Karunadasa
- Department of Chemistry, Stanford University Stanford CA 94305 USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
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2
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Wenny MB, Walter MV, Slavney AH, Mason JA. Generalizable Synthesis of Highly Fluorinated Ionic Liquids. J Phys Chem B 2023; 127:2028-2033. [PMID: 36821528 DOI: 10.1021/acs.jpcb.2c08374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The unique chemistry of fluorocarbons (in particular, their weak intermolecular interactions and high degree of intrinsic free volume) makes them promising building blocks for ionic liquids with high gas capacities. Here, we report a generalizable method for the synthesis of fluorinated ionic liquids, which relies on the evolution of gaseous byproducts to drive product formation. This synthetic strategy overcomes solubility challenges that can hinder the synthesis of highly fluorinated ionic liquids via conventional methods and enables a systematic investigation of the effect of fluorination on ionic liquid viscosity and gas solubility.
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Affiliation(s)
- Malia B Wenny
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Miranda V Walter
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Adam H Slavney
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jarad A Mason
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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3
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Liu M, Slavney AH, Tao S, McGillicuddy RD, Lee CC, Wenny MB, Billinge SJL, Mason JA. Designing Glass and Crystalline Phases of Metal-Bis(acetamide) Networks to Promote High Optical Contrast. J Am Chem Soc 2022; 144:22262-22271. [PMID: 36441167 DOI: 10.1021/jacs.2c10449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Owing to their high tunability and predictable structures, metal-organic materials offer a powerful platform to study glass formation and crystallization processes and to design glasses with unique properties. Here, we report a novel series of glass-forming metal-ethylenebis(acetamide) networks that undergo reversible glass and crystallization transitions below 200 °C. The glass-transition temperatures, crystallization kinetics, and glass stability of these materials are readily tunable, either by synthetic modification or by liquid-phase blending, to form binary glasses. Pair distribution function (PDF) analysis reveals extended structural correlations in both single and binary metal-bis(acetamide) glasses and highlights the important role of metal-metal correlations during structural evolution across glass-crystal transitions. Notably, the glass and crystalline phases of a Co-ethylenebis(acetamide) binary network feature a large reflectivity contrast ratio of 4.8 that results from changes in the local coordination environment around Co centers. These results provide new insights into glass-crystal transitions in metal-organic materials and have exciting implications for optical switching, rewritable data storage, and functional glass ceramics.
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Affiliation(s)
- Mengtan Liu
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Adam H Slavney
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Songsheng Tao
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York10027, United States
| | - Ryan D McGillicuddy
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Cassia C Lee
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Malia B Wenny
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
| | - Simon J L Billinge
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York10027, United States.,Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York11973, United States
| | - Jarad A Mason
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts02138, United States
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4
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Slavney AH, Kim HK, Tao S, Liu M, Billinge SJL, Mason JA. Liquid and Glass Phases of an Alkylguanidinium Sulfonate Hydrogen-Bonded Organic Framework. J Am Chem Soc 2022; 144:11064-11068. [PMID: 35699732 DOI: 10.1021/jacs.2c02918] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glassy phases of framework materials feature unique and tunable properties that are advantageous for gas separation membranes, solid electrolytes, and phase-change memory applications. Here, we report a new guanidinium organosulfonate hydrogen-bonded organic framework (HOF) that melts and vitrifies below 100 °C. In this low-temperature regime, non-covalent interactions between guest molecules and the porous framework become a dominant contributor to the overall stability of the structure, resulting in guest-dependent melting, glass, and recrystallization transitions. Through simulations and X-ray scattering, we show that the local structures of the amorphous liquid and glass phases resemble those of the parent crystalline framework.
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Affiliation(s)
- Adam H Slavney
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Hong Ki Kim
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Songsheng Tao
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Mengtan Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Simon J L Billinge
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States.,Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jarad A Mason
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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5
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Wenny MB, Molinari N, Slavney AH, Thapa S, Lee B, Kozinsky B, Mason JA. Understanding Relationships between Free Volume and Oxygen Absorption in Ionic Liquids. J Phys Chem B 2022; 126:1268-1274. [PMID: 35113543 DOI: 10.1021/acs.jpcb.2c00202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the factors that govern gas absorption in ionic liquids is critical to the development of high-capacity solvents for catalysis, electrochemistry, and gas separations. Here, we report experimental probes of liquid structure that provide insights into how free volume impacts the O2 absorption properties of ionic liquids. Specifically, we establish that isothermal compressibility─measured rapidly and accurately through small-angle X-ray scattering─reports on the size distribution of transient voids within a representative series of ionic liquids and is correlated with O2 absorption capacity. Additionally, O2 absorption capacities are correlated with thermal expansion coefficients, reflecting the beneficial effect of weak intermolecular interactions in ionic liquids on free volume and gas absorption capacity. Molecular dynamics simulations show that the void size distribution─in particular, the probability of forming larger voids within an ionic liquid─has a greater impact on O2 absorption than the total free volume. These results establish relationships between the ionic liquid structure and gas absorption properties that offer design strategies for ionic liquids with high gas solubilities.
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Affiliation(s)
- Malia B Wenny
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Nicola Molinari
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Adam H Slavney
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Surendra Thapa
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Byeongdu Lee
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Boris Kozinsky
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jarad A Mason
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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6
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Affiliation(s)
- Nathan R. Wolf
- Department of Chemistry Stanford University Stanford California 94305 USA
| | - Bridget A. Connor
- Department of Chemistry Stanford University Stanford California 94305 USA
| | - Adam H. Slavney
- Department of Chemistry Stanford University Stanford California 94305 USA
| | - Hemamala I. Karunadasa
- Department of Chemistry Stanford University Stanford California 94305 USA
- Stanford Institute for Materials and Energy Sciences SLAC National Accelerator Laboratory Menlo Park California 94025 USA
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7
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Wolf NR, Connor BA, Slavney AH, Karunadasa HI. Doubling the Stakes: The Promise of Halide Double Perovskites. Angew Chem Int Ed Engl 2021; 60:16264-16278. [DOI: 10.1002/anie.202016185] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Indexed: 01/01/2023]
Affiliation(s)
- Nathan R. Wolf
- Department of Chemistry Stanford University Stanford California 94305 USA
| | - Bridget A. Connor
- Department of Chemistry Stanford University Stanford California 94305 USA
| | - Adam H. Slavney
- Department of Chemistry Stanford University Stanford California 94305 USA
| | - Hemamala I. Karunadasa
- Department of Chemistry Stanford University Stanford California 94305 USA
- Stanford Institute for Materials and Energy Sciences SLAC National Accelerator Laboratory Menlo Park California 94025 USA
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8
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Liu M, McGillicuddy RD, Vuong H, Tao S, Slavney AH, Gonzalez MI, Billinge SJL, Mason JA. Network-Forming Liquids from Metal–Bis(acetamide) Frameworks with Low Melting Temperatures. J Am Chem Soc 2021; 143:2801-2811. [DOI: 10.1021/jacs.0c11718] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mengtan Liu
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Ryan D. McGillicuddy
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Hung Vuong
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Songsheng Tao
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Adam H. Slavney
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Miguel I. Gonzalez
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Simon J. L. Billinge
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Jarad A. Mason
- Department of Chemistry & Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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9
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Girdzis SP, Lin Y, Leppert L, Slavney AH, Park S, Chapman KW, Karunadasa HI, Mao WL. Revealing Local Disorder in a Silver-Bismuth Halide Perovskite upon Compression. J Phys Chem Lett 2021; 12:532-536. [PMID: 33377386 DOI: 10.1021/acs.jpclett.0c03412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The halide double perovskite Cs2AgBiBr6 has emerged as a promising nontoxic alternative to the lead halide perovskites APbX3 (A = organic cation or Cs; X = I or Br). Here, we perform high-pressure synchrotron X-ray total scattering on Cs2AgBiBr6 and discover local disorder that is hidden from conventional Bragg analysis. While our powder diffraction data show that the average structure remains cubic up to 2.1 GPa, analysis of the X-ray pair distribution function reveals that the local structure is better described by a monoclinic space group, with significant distortion within the Ag-Br and Bi-Br octahedra and off-centering of the Cs atoms. By tracking the distribution of interatomic Cs-Br distances, we find that the local disorder is enhanced upon compression, and we corroborate these results with molecular dynamics simulations. The observed local disorder affords new understanding of this promising material and potentially offers a new parameter to tune in halide perovskite lattices.
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Affiliation(s)
- Samuel P Girdzis
- Department of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Yu Lin
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Linn Leppert
- Computational Chemical Physics, MESA+ Institute of Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
- Institute of Physics, University of Bayreuth, 95440 Bayreuth, Germany
| | - Adam H Slavney
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Sulgiye Park
- Department of Geological Sciences, Stanford University, Stanford, California 94305, United States
| | - Karena W Chapman
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Hemamala I Karunadasa
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Wendy L Mao
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Geological Sciences, Stanford University, Stanford, California 94305, United States
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10
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Slavney AH, Connor BA, Leppert L, Karunadasa HI. A pencil-and-paper method for elucidating halide double perovskite band structures. Chem Sci 2019; 10:11041-11053. [PMID: 32190254 PMCID: PMC7066864 DOI: 10.1039/c9sc03219c] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 09/30/2019] [Indexed: 11/21/2022] Open
Abstract
Halide double perovskites are an important emerging alternative to lead-halide perovskites in a variety of optoelectronic applications. Compared to ABX3 single perovskites (A = monovalent cation, X = halide), A2BB'X6 double perovskites exhibit a wider array of compositions and electronic structures, promising finer control over physical and electronic properties through synthetic design. However, a clear understanding of how chemical composition dictates the electronic structures of this large family of materials is still lacking. Herein, we develop a qualitative Linear Combination of Atomic Orbitals (LCAO) model that describes the full range of band structures for double perovskites. Our simple model allows for a direct connection between the inherently local bonding between atoms in the double perovskite and the resulting delocalized bands of the solid. In particular, we show how bands in halide double perovskites originate from the molecular orbitals of metal-hexahalide coordination complexes and describe how these molecular orbitals vary within a band. Our results provide both an enhanced understanding of known perovskite compositions and predictive power for identifying new compositions with targeted properties. We present a table, which permits the position of the conduction band minimum and valence band maximum in most double perovskites to be immediately determined from the frontier atomic orbitals of the B-site metals. Using purely qualitative arguments based on orbital symmetries and their relative energies, the direct/indirect nature of the bandgap of almost all halide double perovskites can thus be correctly predicted. We hope that this theory provides an intuitive understanding of halide double perovskite band structures and enables lessons from molecular chemistry to be applied to these extended solids.
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Affiliation(s)
- Adam H Slavney
- Department of Chemistry , Stanford University , Stanford , CA 94305 , USA .
| | - Bridget A Connor
- Department of Chemistry , Stanford University , Stanford , CA 94305 , USA .
| | - Linn Leppert
- Institute of Physics , University of Bayreuth , Bayreuth , 95440 , Germany
| | - Hemamala I Karunadasa
- Department of Chemistry , Stanford University , Stanford , CA 94305 , USA .
- Stanford Institute for Materials and Energy Sciences , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
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11
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Lindquist KP, Mack SA, Slavney AH, Leppert L, Gold-Parker A, Stebbins JF, Salleo A, Toney MF, Neaton JB, Karunadasa HI. Tuning the bandgap of Cs 2AgBiBr 6 through dilute tin alloying. Chem Sci 2019; 10:10620-10628. [PMID: 32110348 PMCID: PMC7020786 DOI: 10.1039/c9sc02581b] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 09/30/2019] [Indexed: 01/13/2023] Open
Abstract
Sn alloying tunes a halide double perovskite to absorb visible light, in a nontoxic composition.
The promise of lead halide hybrid perovskites for optoelectronic applications makes finding less-toxic alternatives a priority. The double perovskite Cs2AgBiBr6 (1) represents one such alternative, offering long carrier lifetimes and greater stability under ambient conditions. However, the large and indirect 1.95 eV bandgap hinders its potential as a solar absorber. Here we report that alloying crystals of 1 with up to 1 atom% Sn results in a bandgap reduction of up to ca. 0.5 eV while maintaining low toxicity. Crystals can be alloyed with up to 1 atom% Sn and the predominant substitution pathway appears to be a ∼2 : 1 substitution of Sn2+ and Sn4+ for Ag+ and Bi3+, respectively, with Ag+ vacancies providing charge compensation. Spincoated films of 1 accommodate a higher Sn loading, up to 4 atom% Sn, where we see mostly Sn2+ substitution for both Ag+ and Bi3+. Density functional theory (DFT) calculations ascribe the bandgap redshift to the introduction of Sn impurity bands below the conduction band minimum of the host lattice. Using optical absorption spectroscopy, photothermal deflection spectroscopy, X-ray absorption spectroscopy, 119Sn NMR, redox titration, single-crystal and powder X-ray diffraction, multiple elemental analysis and imaging techniques, and DFT calculations, we provide a detailed analysis of the Sn content and oxidation state, dominant substitution sites, and charge-compensating defects in Sn-alloyed Cs2AgBiBr6 (1:Sn) crystals and films. An understanding of heterovalent alloying in halide double perovskites opens the door to a wider breadth of potential alloying agents for manipulating their band structures in a predictable manner.
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Affiliation(s)
- Kurt P Lindquist
- Department of Chemistry , Stanford University , Stanford , California 94305 , USA .
| | - Stephanie A Mack
- Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA . .,Department of Physics , University of California Berkeley , Berkeley , California 94720 , USA
| | - Adam H Slavney
- Department of Chemistry , Stanford University , Stanford , California 94305 , USA .
| | - Linn Leppert
- Department of Physics , University of Bayreuth , 95440 Bayreuth , Germany
| | - Aryeh Gold-Parker
- Department of Chemistry , Stanford University , Stanford , California 94305 , USA . .,Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Jonathan F Stebbins
- Department of Geological Sciences , Stanford University , Stanford , California 94305 , USA
| | - Alberto Salleo
- Department of Materials Science and Engineering , Stanford University , Stanford , California 94305 , USA
| | - Michael F Toney
- Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
| | - Jeffrey B Neaton
- Molecular Foundry , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA . .,Department of Physics , University of California Berkeley , Berkeley , California 94720 , USA.,Kavli Energy NanoScience , Institute at Berkeley , Berkeley , California 94720 , USA
| | - Hemamala I Karunadasa
- Department of Chemistry , Stanford University , Stanford , California 94305 , USA . .,Stanford Institute for Materials and Energy Sciences , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , USA
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12
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Clayman NE, Manumpil MA, Matson BD, Wang S, Slavney AH, Sarangi R, Karunadasa HI, Waymouth RM. Reactivity of NO 2 with Porous and Conductive Copper Azobispyridine Metallopolymers. Inorg Chem 2019; 58:10856-10860. [DOI: 10.1021/acs.inorgchem.9b01190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Naomi E. Clayman
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Mary Anne Manumpil
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Benjamin D. Matson
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Shengkai Wang
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Adam H. Slavney
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Ritimuka Sarangi
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | | | - Robert M. Waymouth
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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13
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Slavney AH, Leppert L, Saldivar Valdes A, Bartesaghi D, Savenije TJ, Neaton JB, Karunadasa HI. Small‐Band‐Gap Halide Double Perovskites. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807421] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Adam H. Slavney
- Department of Chemistry Stanford University Stanford CA 94305 USA
| | - Linn Leppert
- Institute of Physics University of Bayreuth 95440 Bayreuth Germany
| | | | - Davide Bartesaghi
- Department of Chemical Engineering Delft University of Technology Delft Netherlands
- Materials Innovation Institute, 2628CD Delft Netherlands
| | - Tom J. Savenije
- Department of Chemical Engineering Delft University of Technology Delft Netherlands
| | - Jeffrey B. Neaton
- Department of Physics University of California USA
- Molecular Foundry Lawrence Berkeley National Laboratory USA
- Kavli Energy NanoScience, Institute at Berkeley Berkeley CA 94720 USA
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14
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Slavney AH, Leppert L, Saldivar Valdes A, Bartesaghi D, Savenije TJ, Neaton JB, Karunadasa HI. Small-Band-Gap Halide Double Perovskites. Angew Chem Int Ed Engl 2018; 57:12765-12770. [PMID: 30088309 DOI: 10.1002/anie.201807421] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 11/08/2022]
Abstract
Despite their compositional versatility, most halide double perovskites feature large band gaps. Herein, we describe a strategy for achieving small band gaps in this family of materials. The new double perovskites Cs2 AgTlX6 (X=Cl (1) and Br (2)) have direct band gaps of 2.0 and 0.95 eV, respectively, which are approximately 1 eV lower than those of analogous perovskites. To our knowledge, compound 2 displays the lowest band gap for any known halide perovskite. Unlike in AI BII X3 perovskites, the band-gap transition in AI2 BB'X6 double perovskites can show substantial metal-to-metal charge-transfer character. This band-edge orbital composition is used to achieve small band gaps through the selection of energetically aligned B- and B'-site metal frontier orbitals. Calculations reveal a shallow, symmetry-forbidden region at the band edges for 1, which results in long (μs) microwave conductivity lifetimes. We further describe a facile self-doping reaction in 2 through Br2 loss at ambient conditions.
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Affiliation(s)
- Adam H Slavney
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Linn Leppert
- Institute of Physics, University of Bayreuth, 95440, Bayreuth, Germany
| | | | - Davide Bartesaghi
- Department of Chemical Engineering, Delft University of Technology, Delft, Netherlands.,Materials Innovation Institute, 2628CD, Delft, Netherlands
| | - Tom J Savenije
- Department of Chemical Engineering, Delft University of Technology, Delft, Netherlands
| | - Jeffrey B Neaton
- Department of Physics, University of California, USA.,Molecular Foundry, Lawrence Berkeley National Laboratory, USA.,Kavli Energy NanoScience, Institute at Berkeley, Berkeley, CA, 94720, USA
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15
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Bartesaghi D, Slavney AH, Gélvez-Rueda MC, Connor BA, Grozema FC, Karunadasa HI, Savenije TJ. Charge Carrier Dynamics in Cs 2AgBiBr 6 Double Perovskite. J Phys Chem C Nanomater Interfaces 2018; 122:4809-4816. [PMID: 29545908 PMCID: PMC5846080 DOI: 10.1021/acs.jpcc.8b00572] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/01/2018] [Indexed: 05/28/2023]
Abstract
Double perovskites, comprising two different cations, are potential nontoxic alternatives to lead halide perovskites. Here, we characterized thin films and crystals of Cs2AgBiBr6 by time-resolved microwave conductance (TRMC), which probes formation and decay of mobile charges upon pulsed irradiation. Optical excitation of films results in the formation of charges with a yield times mobility product, φΣμ > 1 cm2/Vs. On excitation of millimeter-sized crystals, the TRMC signals show, apart from a fast decay, a long-lived tail. Interestingly, this tail is dominant when exciting close to the bandgap, implying the presence of mobile charges with microsecond lifetimes. From the temperature and intensity dependence of the TRMC signals, we deduce a shallow trap state density of around 1016/cm3 in the bulk of the crystal. Despite this high concentration, trap-assisted recombination of charges in the bulk appears to be slow, which is promising for photovoltaic applications.
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Affiliation(s)
- Davide Bartesaghi
- Department
of Chemical Engineering, Delft University
of Technology, 2628CD Delft, The Netherlands
- Materials
Innovation Institute (M2i), 2628CD Delft, The Netherlands
| | - Adam H. Slavney
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - María C. Gélvez-Rueda
- Department
of Chemical Engineering, Delft University
of Technology, 2628CD Delft, The Netherlands
| | - Bridget A. Connor
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Ferdinand C. Grozema
- Department
of Chemical Engineering, Delft University
of Technology, 2628CD Delft, The Netherlands
| | | | - Tom J. Savenije
- Department
of Chemical Engineering, Delft University
of Technology, 2628CD Delft, The Netherlands
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16
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Slavney AH, Leppert L, Bartesaghi D, Gold-Parker A, Toney MF, Savenije TJ, Neaton JB, Karunadasa HI. Defect-Induced Band-Edge Reconstruction of a Bismuth-Halide Double Perovskite for Visible-Light Absorption. J Am Chem Soc 2017; 139:5015-5018. [PMID: 28353345 DOI: 10.1021/jacs.7b01629] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Halide double perovskites have recently been developed as less toxic analogs of the lead perovskite solar-cell absorbers APbX3 (A = monovalent cation; X = Br or I). However, all known halide double perovskites have large bandgaps that afford weak visible-light absorption. The first halide double perovskite evaluated as an absorber, Cs2AgBiBr6 (1), has a bandgap of 1.95 eV. Here, we show that dilute alloying decreases 1's bandgap by ca. 0.5 eV. Importantly, time-resolved photoconductivity measurements reveal long-lived carriers with microsecond lifetimes in the alloyed material, which is very promising for photovoltaic applications. The alloyed perovskite described herein is the first double perovskite to show comparable bandgap energy and carrier lifetime to those of (CH3NH3)PbI3. By describing how energy- and symmetry-matched impurity orbitals, at low concentrations, dramatically alter 1's band edges, we open a potential pathway for the large and diverse family of halide double perovskites to compete with APbX3 absorbers.
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Affiliation(s)
- Adam H Slavney
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Linn Leppert
- Molecular Foundry, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.,Department of Physics, University of California Berkeley , Berkeley, California 94720, United States
| | - Davide Bartesaghi
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology , 2628CD Delft, The Netherlands.,Materials Innovation Institute (M2i) , 2628CD Delft, The Netherlands
| | - Aryeh Gold-Parker
- Department of Chemistry, Stanford University , Stanford, California 94305, United States.,Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Michael F Toney
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Tom J Savenije
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology , 2628CD Delft, The Netherlands
| | - Jeffrey B Neaton
- Molecular Foundry, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.,Department of Physics, University of California Berkeley , Berkeley, California 94720, United States.,Kavli Energy NanoScience, Institute at Berkeley , Berkeley, California 94720, United States
| | - Hemamala I Karunadasa
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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17
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Slavney AH, Smaha RW, Smith IC, Jaffe A, Umeyama D, Karunadasa HI. Chemical Approaches to Addressing the Instability and Toxicity of Lead-Halide Perovskite Absorbers. Inorg Chem 2016; 56:46-55. [PMID: 27494338 DOI: 10.1021/acs.inorgchem.6b01336] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The impressive rise in efficiencies of solar cells employing the three-dimensional (3D) lead-iodide perovskite absorbers APbI3 (A = monovalent cation) has generated intense excitement. Although these perovskites have remarkable properties as solar-cell absorbers, their potential commercialization now requires a greater focus on the materials' inherent shortcomings and environmental impact. This creates a challenge and an opportunity for synthetic chemists to address these issues through the design of new materials. Synthetic chemistry offers powerful tools for manipulating the magnificent flexibility of the perovskite lattice to expand the number of functional analogues to APbI3. To highlight improvements that should be targeted in new materials, here we discuss the intrinsic instability and toxicity of 3D lead-halide perovskites. We consider possible sources of these instabilities and propose methods to overcome them through synthetic design. We also discuss new materials developed for realizing the exceptional photophysical properties of lead-halide perovskites in more environmentally benign materials. In this Forum Article, we provide a brief overview of the field with a focus on our group's contributions to identifying and addressing problems inherent to 3D lead-halide perovskites.
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Affiliation(s)
- Adam H Slavney
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Rebecca W Smaha
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Ian C Smith
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Adam Jaffe
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Daiki Umeyama
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Hemamala I Karunadasa
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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18
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Slavney AH, Hu T, Lindenberg AM, Karunadasa HI. A Bismuth-Halide Double Perovskite with Long Carrier Recombination Lifetime for Photovoltaic Applications. J Am Chem Soc 2016; 138:2138-41. [PMID: 26853379 DOI: 10.1021/jacs.5b13294] [Citation(s) in RCA: 566] [Impact Index Per Article: 70.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Despite the remarkable rise in efficiencies of solar cells containing the lead-halide perovskite absorbers RPbX3 (R = organic cation; X = Br(-) or I(-)), the toxicity of lead remains a concern for the large-scale implementation of this technology. This has spurred the search for lead-free materials with similar optoelectronic properties. Here, we use the double-perovskite structure to incorporate nontoxic Bi(3+) into the perovskite lattice in Cs2AgBiBr6 (1). The solid shows a long room-temperature fundamental photoluminescence (PL) lifetime of ca. 660 ns, which is very encouraging for photovoltaic applications. Comparison between single-crystal and powder PL decay curves of 1 suggests inherently high defect tolerance. The material has an indirect bandgap of 1.95 eV, suited for a tandem solar cell. Furthermore, 1 is significantly more heat and moisture stable compared to (MA)PbI3. The extremely promising optical and physical properties of 1 shown here motivate further exploration of both inorganic and hybrid halide double perovskites for photovoltaics and other optoelectronics.
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Affiliation(s)
- Adam H Slavney
- Departments of †Chemistry and §Materials Science and Engineering, Stanford University , Stanford, California 94305, United States
| | - Te Hu
- Departments of †Chemistry and §Materials Science and Engineering, Stanford University , Stanford, California 94305, United States
| | - Aaron M Lindenberg
- Departments of †Chemistry and §Materials Science and Engineering, Stanford University , Stanford, California 94305, United States
| | - Hemamala I Karunadasa
- Departments of †Chemistry and §Materials Science and Engineering, Stanford University , Stanford, California 94305, United States
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