Phase Transitions in CsSnCl<sub>3</sub> and CsPbBr<sub>3</sub> An NMR and NQR Study

Sharma, Sushmita; Weiden, Norbert; Weiß, Alarich

doi:10.1515/zna-1991-0406

Cited by 32 publications

(37 citation statements)

References 14 publications

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“…All four materials exist in the highest symmetry cubic α phase at room temperature. 36,63,98 Also in this case, the line broadening was numerically simulated and is attributed to fast quadrupolar relaxation of 79/81 Br bound to 119 Sn ( Figure S7).…”

Section: ■ Results and Discussionmentioning

confidence: 85%

“…This phase is metastable and can be transformed back to the low-symmetry phase in the presence of humidity. 98 Finally, we note that 119 Sn can be used to study the halide coordination environment in tin(II) halides perovskites not only when the A site is an organic cation (Figures 2 and 3) but also when it is an inorganic cation such Journal of the American Chemical Society pubs.acs.org/JACS Article as cesium. Figure 4m shows that the 119 119 Sn MAS NMR is well-suited for probing the atomic-level microstructure of mixed-cation and mixed-anion tin(II) halide perovskites, as it is highly sensitive to both the A-site and X-site composition.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

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Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from ¹¹⁹Sn Solid-State NMR

et al. 2020

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Organic−inorganic tin(II) halide perovskites have emerged as promising alternatives to lead halide perovskites in optoelectronic applications. While they suffer from considerably poorer performance and stability in comparison to their lead analogues, their performance improvements have so far largely been driven by trial and error efforts due to a critical lack of methods to probe their atomic-level microstructure. Here, we identify the challenges and devise a 119 Sn solid-state NMR protocol for the determination of the local structure of mixed-cation and mixed-halide tin(II) halide perovskites as well as their degradation products and related phases. We establish that the longitudinal relaxation of 119 Sn can span 6 orders of magnitude in this class of compounds, which makes judicious choice of experimental NMR parameters essential for the reliable detection of various phases. We show that Cl/Br and I/Br mixed-halide perovskites form solid alloys in any ratio, while only limited mixing is possible for I/Cl compositions. We elucidate the degradation pathways of Cs-, MA-, and FA-based tin(II) halides and show that degradation leads to highly disordered, qualitatively similar products, regardless of the A-site cation and halide. We detect the presence of metallic tin among the degradation products, which we suggest could contribute to the previously reported high conductivities in tin(II) halide perovskites. 119 Sn NMR chemical shifts are a sensitive probe of the halide coordination environment as well as of the A-site cation composition. Finally, we use variable-temperature multifield relaxation measurements to quantify ion dynamics in MASnBr 3 and establish activation energies for motion and show that this motion leads to spontaneous halide homogenization at room temperature whenever two different pure-halide perovskites are put in physical contact.

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Section: ■ Results and Discussionmentioning

confidence: 85%

Section: ■ Results and Discussionmentioning

confidence: 98%

Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from ¹¹⁹Sn Solid-State NMR

et al. 2020

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“…This difference shows a significant structural change occurs within CsPbBr 3 below room temperature, as further supported by temperaturedependent THz and HR-TEM measurements and supported with theoretical calculations discussed later. Structural phase changes have been reported in CsPbBr 3 at 361 K, where there is an orthorhombic-to-tetragonal phase transition, and at 403 K, where the phase transition is from tetragonal to cubic 18,19,36,37 , both of which occur above room temperature. A significant change can also be seen in the complex dielectric function of the second sample between 360 and 370 K in Supplementary Fig.…”

Section: Resultsmentioning

confidence: 98%

“…Several materials have exhibited structural phase duality, such as nanocrystalline Ni 45 , Cu 3 SnS 4 nanocrystals 46 , and most notably, Na 0.5 Bi 0.5 -TiO 3 perovskite, where structural phase duality exists over two temperature ranges: the tetragonal/cubic phase between 773 and 813 K and the rhombohedral/tetragonal phase over 528-673 K 47 . In this case, the optical transitions associated with the orthorhombic phase begin to appear at 361 K, which is the temperature at which the single-crystal phase change was recorded 12,19,36,37 . The peaks associated with the transitions become stronger as CsPbBr 3 cools to 7 K, which would make it the largest recorded temperature range over which a structural phase duality exists.…”

Section: Resultsmentioning

confidence: 99%

Dual phases of crystalline and electronic structures in the nanocrystalline perovskite CsPbBr3

et al. 2019

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Inorganic perovskites have recently attracted much attention as promising new nanocrystalline materials that have interesting fundamental phenomena and great potential in several applications. Herein, we reveal unusual structural and electronic changes in nanocrystalline cesium lead bromide (CsPbBr 3 ) as a function of temperature using highresolution spectroscopic ellipsometry, high-resolution transmission electron microscopy and terahertz spectroscopy measurements supported by first-principles calculations. New dual phases of crystalline and electronic structures are observed due to the nanocrystalline nature of the material. Interestingly, a change in the electronic structure occurs below 150 K, and the rate at which the nanocrystal transitions from the tetragonal to orthorhombic phase is found to be nonlinear with temperature. Our results show the importance of the charge and lattice interplay in determining the dual phases and fundamental properties of nanocrystalline materials.

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“…As to the halides, NMR spectroscopy had thus far been hampered by their large quadrupolar constants, leading to massively broadened signals and distorted line shapes 52,53 . For this reason, halides are more commonly assessed with nuclear quadrupole resonance (NQR) spectroscopy 25,44,[54][55][56][57][58] . Sharma et al 59 (1987) and the dissertation by Ullmann (1998) 60 are, to our knowledge, the first reports on 207 Pb NMR of lead-halide perovskites.…”

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confidence: 99%

Lead-Halide Scalar Couplings in 207Pb NMR of APbX3 Perovskites (A = Cs, Methylammonium, Formamidinium; X = Cl, Br, I)

Aebli

Piveteau

Nazarenko

et al. 2020

Sci Rep

110

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Understanding the structure and dynamics of newcomer optoelectronic materials-lead halide perovskites ApbX 3 [A = cs, methylammonium (cH 3 nH 3 + , MA), formamidinium (cH(nH 2) 2 + , fA); X = cl, Br, i]-has been a major research thrust. in this work, new insights could be gained by using 207 pb solid-state nuclear magnetic resonance (nMR) spectroscopy at variable temperatures between 100 and 300 K. The existence of scalar couplings 1 J pb-cl of ca. 400 Hz and 1 J pb-Br of ca. 2.3 kHz could be confirmed for MAPbX 3 and cspbX 3. Diverse and fast structure dynamics, including rotations of A-cations, harmonic and anharmonic vibrations of the lead-halide framework and ionic mobility, affect the resolution of the coupling pattern. 207 pb nMR can therefore be used to detect the structural disorder and phase transitions. furthermore, by comparing bulk and nanocrystalline cspbBr 3 a greater structural disorder of the pbBr 6-octahedra had been confirmed in a nanoscale counterpart, not readily captured by diffraction-based techniques. Semiconducting lead halide perovskite materials, foremost of APbX 3-type [A = Cs, methylammonium (CH 3 NH 3 + , MA), formamidinium (CH(NH 2) 2 + , FA); X = Cl, Br, I], have raised tremendous interest over the past years due to their outstanding optoelectronic properties, which find application in solar cells 1,2 , X-ray 3 and gamma detectors 4-6 and light-emitting devices 7-14. These semiconductors exhibit unusually high defect-tolerance, which is the nearly intrinsic semiconducting behaviour in spite of the high abundance of structural imperfections. Such defect-tolerance had been attributed to the specifics of the electronic structure, crystal structure and structural dynamics 15-21. It is therefore fundamental to develop an experimental toolset and a related mind-set for studying the local structure and structural dynamics as well as their relationship to the electronic and physical properties of these semiconductors. Solid-state nuclear magnetic resonance (NMR) is a powerful technique for characterizing solid materials. It is complementary to X-ray diffraction, as it is particularly sensitive to the local environment of nuclei. Chemical composition of APbX 3 makes these compounds very well suited for NMR, owing to the range of NMR-active nuclei (1

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Phase Transitions in CsSnCl₃ and CsPbBr₃ An NMR and NQR Study

Cited by 32 publications

References 14 publications

Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from ¹¹⁹Sn Solid-State NMR

Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from ¹¹⁹Sn Solid-State NMR

Dual phases of crystalline and electronic structures in the nanocrystalline perovskite CsPbBr3

Lead-Halide Scalar Couplings in 207Pb NMR of APbX3 Perovskites (A = Cs, Methylammonium, Formamidinium; X = Cl, Br, I)

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Phase Transitions in CsSnCl3 and CsPbBr3 An NMR and NQR Study

Cited by 32 publications

References 14 publications

Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from 119Sn Solid-State NMR

Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from 119Sn Solid-State NMR

Dual phases of crystalline and electronic structures in the nanocrystalline perovskite CsPbBr3

Lead-Halide Scalar Couplings in 207Pb NMR of APbX3 Perovskites (A = Cs, Methylammonium, Formamidinium; X = Cl, Br, I)

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Product

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Phase Transitions in CsSnCl₃ and CsPbBr₃ An NMR and NQR Study

Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from ¹¹⁹Sn Solid-State NMR

Local Structure and Dynamics in Methylammonium, Formamidinium, and Cesium Tin(II) Mixed-Halide Perovskites from ¹¹⁹Sn Solid-State NMR