1
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López C, Abia C, Gainza J, Rodrigues JE, Martinelli B, Serrano-Sánchez F, Silva RS, Ferrer MM, Dura OJ, Martínez JL, Fernández-Díaz MT, Alonso JA. Unveiling the Structural Properties, Optical Behavior, and Thermoelectric Performance of 2D CsSn 2Br 5 Halide Obtained by Mechanochemistry. Inorg Chem 2024; 63:12641-12650. [PMID: 38920333 PMCID: PMC11234366 DOI: 10.1021/acs.inorgchem.4c01861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 06/12/2024] [Accepted: 06/18/2024] [Indexed: 06/27/2024]
Abstract
Metal halide perovskites with a two-dimensional structure are utilized in photovoltaics and optoelectronics. High-crystallinity CsSn2Br5 specimens have been synthesized via ball milling. Differential scanning calorimetry curves show melting at 553 K (endothermic) and recrystallization at 516 K (exothermic). Structural analysis using synchrotron X-ray diffraction data, collected from 100 to 373 K, allows for the determination of Debye model parameters. This analysis provides insights into the relative Cs-Br and Sn-Br chemical bonds within the tetragonal structure (space group: I4/mcm), which remains stable throughout the temperature range studied. Combined with neutron data, X-N techniques permit the identification of the Sn2+ lone electron pair (5s2) in the two-dimensional framework, occupying empty space opposite to the four Sn-Br bonds of the pyramidal [SnBr4] coordination polyhedra. Additionally, diffuse reflectance UV-vis spectroscopy unveils an indirect optical gap of approximately ∼3.3 eV, aligning with the calculated value from the B3LYP-DFT method (∼3.2 eV). The material exhibits a positive Seebeck coefficient as high as 6.5 × 104 μV K-1 at 350 K, which evolves down to negative values of -3.0 × 103 μV K-1 at 550 K, surpassing values reported for other halide perovskites. Notably, the thermal conductivity remains exceptionally low, between 0.32 and 0.25 W m-1 K-1.
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Affiliation(s)
- Carlos
Alberto López
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
- INTEQUI,
(UNSL-CONICET) and Facultad de Química, Bioquímica y
Farmacia, UNSL, Almirante
Brown 1455, 5700 San Luis, Argentina
| | - Carmen Abia
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
- Institut
Laue Langevin, 38042 Grenoble, Cedex, France
| | - Javier Gainza
- European Synchrotron
Radiation Facility (ESRF), 71 Avenue des Martyrs, 38000 Grenoble, France
| | - João Elias Rodrigues
- CELLS−ALBA
Synchrotron Light Facility, Cerdanyola del Valles, Barcelona E-08290, Spain
| | - Brenda Martinelli
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, 96010-610 Pelotas, Rio Grande do Sul, Brazil
| | | | - Romualdo Santos Silva
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
| | - Mateus M. Ferrer
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, 96010-610 Pelotas, Rio Grande do Sul, Brazil
| | - Oscar J. Dura
- Departamento
de Física Aplicada, Universidad de
Castilla-La Mancha, Ciudad
Real E-13071, Spain
| | - José Luis Martínez
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
| | | | - José Antonio Alonso
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
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2
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Simenas M, Gagor A, Banys J, Maczka M. Phase Transitions and Dynamics in Mixed Three- and Low-Dimensional Lead Halide Perovskites. Chem Rev 2024; 124:2281-2326. [PMID: 38421808 PMCID: PMC10941198 DOI: 10.1021/acs.chemrev.3c00532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/15/2023] [Accepted: 02/09/2024] [Indexed: 03/02/2024]
Abstract
Lead halide perovskites are extensively investigated as efficient solution-processable materials for photovoltaic applications. The greatest stability and performance of these compounds are achieved by mixing different ions at all three sites of the APbX3 structure. Despite the extensive use of mixed lead halide perovskites in photovoltaic devices, a detailed and systematic understanding of the mixing-induced effects on the structural and dynamic aspects of these materials is still lacking. The goal of this review is to summarize the current state of knowledge on mixing effects on the structural phase transitions, crystal symmetry, cation and lattice dynamics, and phase diagrams of three- and low-dimensional lead halide perovskites. This review analyzes different mixing recipes and ingredients providing a comprehensive picture of mixing effects and their relation to the attractive properties of these materials.
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Affiliation(s)
- Mantas Simenas
- Faculty
of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Anna Gagor
- Institute
of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, PL-50-422 Wroclaw, Poland
| | - Juras Banys
- Faculty
of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Miroslaw Maczka
- Institute
of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, PL-50-422 Wroclaw, Poland
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3
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Zhang K, Zhang L, Saravana Karthikeyan SKS, Kong CY, Zhang F, Guo X, Dang NN, Ramaraj SG, Liu X. Structural, electronic, optical, elastic, thermodynamic and thermal transport properties of Cs 2AgInCl 6 and Cs 2AgSbCl 6 double perovskite semiconductors using a first-principles study. Phys Chem Chem Phys 2023; 25:31848-31868. [PMID: 37968998 DOI: 10.1039/d3cp03795a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
In this study, we employ the framework of first-principles density functional theory (DFT) computations to investigate the physical, electrical, bandgap and thermal conductivity of Cs2AgInCl6-CAIC (type I) and Cs2AgSbCl6-CASC (type II) using the GGA-PBE method. CAIC possesses a direct band gap energy of 1.812 eV, while CASC demonstrates an indirect band gap energy of 0.926 eV. The CAIC and CASC exhibit intriguingly reduced thermal conductivity, which can be attributed to the notable reduction in their respective Debye temperatures, measuring 182 K and 135 K, respectively. The Raman active modes computed under ambient conditions have been compared with real-world data, showing excellent agreement. The thermal conductivity values of CAIC and CASC compounds exhibit quantum mechanical characteristics, with values of 0.075 and 0.25 W m-1 K-1, respectively, at 300 K. It is foreseen that these outcomes will generate investigations concerning phosphors and diodes that rely on single emitters, with the aim of advancing lighting and display technologies in the forthcoming generations.
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Affiliation(s)
- Keqing Zhang
- School of Chemical Engineering, Henan Technical Institute, Zhengzhou, Henan, 450042, P. R. China
| | - Lijun Zhang
- School of Chemical Engineering, Henan Technical Institute, Zhengzhou, Henan, 450042, P. R. China
| | - S K S Saravana Karthikeyan
- Department of Environment and Energy System, Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
| | - Chang Yi Kong
- Department of Environment and Energy System, Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
- Department of Applied Chemistry and Biochemical Engineering, Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
| | - Fuchun Zhang
- School of Physics and Electronic Information, Yan'an University, Yan'an, 716000, China
| | - Xiang Guo
- Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang 441003, Hubei, China.
| | - Nam Nguyen Dang
- Future Materials & Devices Lab., Institute of Fundamental and Applied Sciences, Duy Tan University, Ho Chi Minh City, Vietnam
- The Faculty of Environmental and Chemical Engineering, Duy Tan University, Danang, Vietnam
| | - Sankar Ganesh Ramaraj
- Department of Bioengineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-8656, Japan.
- Department of Materials Physics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences (SIMTS), Thandalam, Chennai - 602105, Tamilnadu, India
| | - Xinghui Liu
- Science and Technology on Aerospace Chemical Power Laboratory, Hubei Institute of Aerospace Chemotechnology, Xiangyang 441003, Hubei, China.
- Division of Research and Development, Lovely Professional University, Phagwara, 144411, India
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4
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Abia C, López CA, Gainza J, Rodrigues JES, Fragoso B, Ferrer MM, Fernández-Díaz MT, Fauth F, Martínez JL, Alonso JA. Structural Features and Optical Properties of All-Inorganic Zero-Dimensional Halides Cs 4PbBr 6-xI x Obtained by Mechanochemistry. ACS APPLIED MATERIALS & INTERFACES 2023; 15:40762-40771. [PMID: 37595125 PMCID: PMC10472433 DOI: 10.1021/acsami.3c07707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/07/2023] [Indexed: 08/20/2023]
Abstract
Despite the great success of hybrid CH3NH3PbI3 perovskite in photovoltaics, ascribed to its excellent optical absorption properties, its instability toward moisture is still an insurmountable drawback. All-inorganic perovskites are much less sensitive to humidity and have potential interest for solar cell applications. Alternative strategies have been developed to design novel materials with appealing properties, which include different topologies for the octahedral arrangements from three-dimensional (3D, e.g., CsPbBr3 perovskite) or two-dimensional (2D, e.g., CsPb2Br5) to zero-dimensional (0D, i.e., without connection between octahedra), as the case of Cs4PbX6 (X = Br, I) halides. The crystal structure of these materials is complex, and their thermal evolution is unexplored. In this work, we describe the synthesis of Cs4PbBr6-xIx (x = 0, 2, 4, 6) halides by mechanochemical procedures with green credentials; these specimens display excellent crystallinity enabling a detailed structural investigation from synchrotron X-ray powder diffraction (SXRD) data, essential to revisit some features in the temperature range of 90-298 K. In all this regime, the structure is defined in the trigonal R3̅c space group (#167). The presence of Cs and X vacancies suggests some ionic mobility into the crystal structure of these 0D halides. Bond valence maps (BVMs) are useful in determining isovalent surfaces for both Cs4PbBr6 and Cs4PbI6 phases, unveiling the likely ionic pathways for cesium and bromide ions and showing a full 3D connection in the bromide phase, in contrast to the iodide one. On the other hand, the evolution of the anisotropic displacement parameters is useful to evaluate the Debye temperatures, confirming that Cs atoms have more freedom to move, while Pb is more confined at its site, likely due to a higher covalency degree in Pb-X bonds than that in Cs-X bonds. Diffuse reflectance ultraviolet-visible (UV-vis) spectroscopy shows that the optical band gap can be tuned depending on iodine content (x) in the range of 3.6-3.06 eV. From density functional theory (DFT) simulations, the general trend of reducing the band gap when Br is replaced by I is well reproduced.
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Affiliation(s)
- Carmen Abia
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
- Institut
Laue Langevin, BP 156X, Grenoble F-38042, France
| | - Carlos A. López
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
- INTEQUI,
(UNSL-CONICET) and Facultad de Química, Bioquímica y
Farmacia, UNSL, Almirante
Brown 1455, 5700 San Luis, Argentina
| | - Javier Gainza
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
| | - João Elias
F. S. Rodrigues
- CELLS−ALBA
Synchrotron, Cerdanyola
del Valles, Barcelona E-08290, Spain
- European
Synchrotron Radiation Facility (ESRF), 38000 Grenoble Cedex, France
| | - Brenda Fragoso
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, 96010-610 Pelotas, Rio Grande do Sul, Brazil
| | - Mateus M. Ferrer
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, 96010-610 Pelotas, Rio Grande do Sul, Brazil
| | | | - François Fauth
- CELLS−ALBA
Synchrotron, Cerdanyola
del Valles, Barcelona E-08290, Spain
| | - José Luis Martínez
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
| | - José Antonio Alonso
- Instituto
de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
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5
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AlKaream Taher HA, Abd AN, Jafar AM. Organo-Lead Halide Perovskite Materials CH 3NH 3PbI 2X, X is I, Br, or Cl, in Solar Cell Applications. INTERNATIONAL JOURNAL OF NANOSCIENCE 2023; 22. [DOI: 10.1142/s0219581x23500229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
The optoelectronic response of organic perovskite solar cells (OPSCs) exhibits a variety of unique and distinguishing characteristics. In this study, OPSCs with photosensitizers, CH3NH3PbI2X, where X is I, Br, or Cl, are created using TiO2 as the electron transport material (ETM) and CuO as the hole transport material (HTM). The perovskite materials’ structural and optical characteristics, as well as the OPSCs’ ETM layers, are investigated. Next, the OPSC’s performance is evaluated. The integrated cell tester, which includes the I-V photovoltaic measurements system and the solar simulation system, was used to measure the I-V curves of the OPSCs. The photovoltaic devices with MAPbI3 as an efficient absorption layer had the best power conversion efficiency [Formula: see text]. Measurements of the OPSC’s performance were tested at 100[Formula: see text]mW/cm2 of light intensity.
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Affiliation(s)
| | - Ahmed N. Abd
- Physics Department, College of Science, Al-Mustansiriah University, Baghdad, Iraq
| | - Aqel Mashot Jafar
- Solar Energy Center, Renewable Energy Directorate, Ministry of Science and Technology, Baghdad, Iraq
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6
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Abia C, López CA, Gainza J, Rodrigues JEFS, Ferrer MM, Dalenogare G, Nemes NM, Dura OJ, Martínez JL, Fernández-Díaz MT, Álvarez-Galván C, Alonso JA. Detailed Structural Features of the Perovskite-Related Halide RbPbI 3 for Solar Cell Applications. Inorg Chem 2022; 61:5502-5511. [PMID: 35344352 PMCID: PMC9006220 DOI: 10.1021/acs.inorgchem.1c03841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
All-inorganic lead halide perovskites like CsPbBr3, CsPbI3, or RbPbI3 are good replacements for the classical hybrid organic-inorganic perovskites like CH3NH3PbI3, susceptible to fast degradation in the presence of humid air. They also exhibit outstanding light absorption properties suitable for solar energy applications. Here, we describe the synthesis of RbPbI3 by mechanochemical procedures with green credentials, avoiding toxic or expensive organic solvents; this specimen exhibits excellent crystallinity. We report neutron powder diffraction data, essential to revisit some subtle structural features around room temperature (200-400 K). In all these regimes, the orthorhombic Pnma crystal structure is characterized by the presence along the b direction of the crystal of double rows of edge-sharing PbI6 octahedra. The lone electron pairs of Pb2+ ions have a strong stereochemical effect on the PbI6 octahedral distortion. The relative covalency of Rb-I versus Pb-I bonds shows that the Pb-I-related motions are more rigid than Rb-I-related vibrations, as seen in the Debye temperatures from the evolution of the anisotropic displacements. The optical gap, measured by diffuse reflectance UV-vis spectroscopy, is ∼2.51 eV and agrees well with ab initio calculations. The thermoelectric Seebeck coefficient is 3 orders of magnitude larger than that of other halide perovskites, with a value of ∼117,000 μV·K-1 at 460 K.
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Affiliation(s)
- Carmen Abia
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain.,Institut Laue Langevin, BP 156X, Grenoble F-38042, France
| | - Carlos A López
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain.,Instituto de Investigaciones en Tecnología Química (UNSL-CONICET) and Facultad de Química, Bioquímica y Farmacia, Almirante Brown 1455, San Luis 5700, Argentina
| | - Javier Gainza
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain
| | - João Elias F S Rodrigues
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain.,European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, Grenoble 38000, France
| | - Mateus M Ferrer
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, Pelotas 96010-610, Rio Grande do Sul, Brazil
| | - Gustavo Dalenogare
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, Pelotas 96010-610, Rio Grande do Sul, Brazil
| | - Norbert M Nemes
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain.,Departamento de Física de Materiales, Universidad Complutense de Madrid, Madrid E-28040, Spain
| | - Oscar J Dura
- Departamento de Física Aplicada, Universidad de Castilla-La Mancha, Ciudad Real E-13071, Spain
| | - José L Martínez
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain
| | | | | | - José A Alonso
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain
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7
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Minussi FB, A Silva L, Araújo EB. Structure, optoelectronic properties and thermal stability of the triple organic cation GA xFA xMA 1-2xPbI 3 system prepared by mechanochemical synthesis. Phys Chem Chem Phys 2022; 24:4715-4728. [PMID: 35137746 DOI: 10.1039/d1cp04977a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Halide perovskites are a well-known class of materials with many interesting applications. Great attention has been devoted to investigating halide perovskites containing triple methylammonium (MA+), formamidinium (FA+), and guanidinium (GA+) cations. Despite presenting very good applied perspectives so far, the lack of fundamental information for this system, such as its structural, thermal, and optoelectronic characteristics, prompts a step back before any technological leap forward. In the present work, we investigate the physical properties of mechanochemically solvent-free synthesized GAxFAxMA1-2xPbI3 halide perovskite powders with compositions of 0.00 ≤ x ≤ 0.15. We demonstrate that the synthesis of the powders can be performed by a simple manual mechanical grinding of the precursors for about 40 minutes, leading to solid solutions with an only minor content of unreacted precursors. X-ray diffraction, differential scanning calorimetry, and infrared spectroscopy techniques were used to investigate the structure, tetragonal-to-cubic phase transition, and vibrational characteristics of the organic cations with increasing GA+ and FA+ contents, respectively. The band gap and Urbach energies, obtained from ultraviolet-visible spectroscopy analyses, ranged from 1.58 to 1.65 eV and 23 to 36 meV, respectively, depending on the composition. These parameters demonstrate a non-random variation with x composition, which offers the possibility of a rational composition design for a given set of desired properties, demonstrating potential for optoelectronic applications. Finally, the system appears to have adequately tolerated heating for 12 hours at 120 °C in an ambient atmosphere, indicating high thermal stability and low ionic conductivity, which are desirable characteristics for solar cell applications.
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Affiliation(s)
- F B Minussi
- Department of Physics and Chemistry, São Paulo State University, 15385-000 Ilha Solteira, Brazil.
| | - L A Silva
- Department of Engineering, University of Rio Verde, 75901-970 Rio Verde, Brazil
| | - E B Araújo
- Department of Physics and Chemistry, São Paulo State University, 15385-000 Ilha Solteira, Brazil.
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8
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Mechano-Chemical Synthesis, Structural Features and Optical Gap of Hybrid CH 3NH 3CdBr 3 Perovskite. MATERIALS 2021; 14:ma14206039. [PMID: 34683627 PMCID: PMC8538067 DOI: 10.3390/ma14206039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/30/2021] [Accepted: 10/08/2021] [Indexed: 11/16/2022]
Abstract
Hybrid methyl-ammonium (MA:CH3NH3+) lead halide MAPbX3 (X = halogen) perovskites exhibit an attractive optoelectronic performance that can be applied to the next generation of solar cells. To extend the field of interest of these hybrid materials, we describe the synthesis by a solvent-free ball-milling procedure, yielding a well crystallized, pure and moisture stable specimen of the Cd tribromide counterpart, MACdBr3, which contains chains of face-sharing CdBr6 octahedra in a framework defined in the Cmc21 (No 36) space group. The details of the structural arrangement at 295 K have been investigated by high angular resolution synchrotron x-ray diffraction (SXRD), including the orientation of the organic MA units, which are roughly aligned along the c direction, given the acentric nature of the space group. UV-vis spectra unveil a gap of 4.6 eV, which could be useful for ultraviolet detectors.
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9
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Rodrigues JEFS, Escanhoela CA, Fragoso B, Sombrio G, Ferrer MM, Álvarez-Galván C, Fernández-Díaz MT, Souza JA, Ferreira FF, Pecharromán C, Alonso JA. Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs2AgSbCl6 Double Perovskite. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c02188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Carlos A. Escanhoela
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170, Santo André, Sao Paulo Brazil
| | - Brenda Fragoso
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, 96010-610 Pelotas, Rio Grande do Sul Brazil
| | - Guilherme Sombrio
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170, Santo André, Sao Paulo Brazil
| | - Mateus M. Ferrer
- CCAF, PPGCEM/CDTec, Federal University of Pelotas, 96010-610 Pelotas, Rio Grande do Sul Brazil
| | | | | | - Jose A. Souza
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170, Santo André, Sao Paulo Brazil
| | - Fabio F. Ferreira
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170, Santo André, Sao Paulo Brazil
| | - Carlos Pecharromán
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, Spain
| | - José Antonio Alonso
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid, Spain
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10
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Lehmann AG, Congiu F, Marongiu D, Mura A, Filippetti A, Mattoni A, Saba M, Pegna G, Sarritzu V, Quochi F, Bongiovanni G. Long-lived electrets and lack of ferroelectricity in methylammonium lead bromide CH 3NH 3PbBr 3 ferroelastic single crystals. Phys Chem Chem Phys 2021; 23:3233-3245. [PMID: 33465210 DOI: 10.1039/d0cp05918h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hybrid lead halides CH3NH3PbX3 (X = I, Br, and Cl) have emerged as a new class of semiconductors for low-cost optoelectronic devices with superior performance. Since their perovskite crystal structure may have lattice instabilities against polar distortions, they are also being considered as potential photo-ferroelectrics. However, so far, research on their ferroelectricity has yielded inconclusive results and the subject is far from being settled. Here, we investigate, using a combined experimental and theoretical approach, the possible presence of electric polarization in tetragonal and orthorhombic CH3NH3PbBr3 (T-MAPB and O-MAPB). We found that T-MAPB does not sustain spontaneous polarization but, under an external electric field, it is projected into a metastable, ionic space-charge electret state. The electret can be frozen on cooling, producing a large and long-lasting polarization in O-MAPB. Molecular dynamics simulations show that the ferroelastic domain boundaries are able to trap charges and segregate ionic point defects, thus playing a favorable role in the stabilization of the electret. At lower temperatures, the lack of ferroelectric behavior is explained using first principles calculations as the result of the tight competition among many metastable states with randomly oriented polarization; this large configurational entropy does not allow a single polar state to dominate at any significant temperature range.
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11
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Enhanced stability in CH 3NH 3PbI 3 hybrid perovskite from mechano-chemical synthesis: structural, microstructural and optoelectronic characterization. Sci Rep 2020; 10:11228. [PMID: 32641694 PMCID: PMC7343856 DOI: 10.1038/s41598-020-68085-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/11/2020] [Indexed: 11/08/2022] Open
Abstract
Among the hybrid organic-inorganic perovskites MAPbX3 (MA: methyl-ammonium CH3-NH3+, X = halogen), the triiodide specimen (MAPbI3) is still the material of choice for solar energy applications. Although it is able to absorb light above its 1.6 eV bandgap, its poor stability in humid air atmosphere has been a major drawback for its use in solar cells. However, we discovered that this perovskite can be prepared by ball milling in a straightforward way, yielding specimens with a superior stability. This fact allowed us to take atomic-resolution STEM images for the first time, with sufficient quality to unveil microscopic aspects of this material. We demonstrated full Iodine content, which might be related to the enhanced stability, in a more compact PbI6 framework with reduced unit-cell volume. A structural investigation from neutron powder diffraction (NPD) data of an undeuterated specimen was essential to determine the configuration of the organic MA unit in the 100-298 K temperature range. A phase transition is identified, from the tetragonal structure observed at RT (space group I4/mcm) to an orthorhombic (space group Pnma) phase where the methyl-ammonium organic units are fully localized. Our NPD data reveal that the MA changes are gradual and start before reaching the phase transition. Optoelectronic measurements yield a photocurrent peak at an illumination wavelength of 820 nm, which is redshifted by 30 nm with respect to previously reported measurements on MAPbI3 perovskites synthesized by crystallization from organic solvents.
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