Determining Electron Spin-Transfer Mechanisms in Paramagnetic Ba2YMO6 (M = Mo, Re, Ru) Double Perovskites by 89Y and 137Ba MAS NMR Spectroscopy

Michaelis, Vladimir K.; Greer, Brandon J.; Aharen, Tomoko; Greedan, John E.; Kroeker, Scott

doi:10.1021/jp308214d

Cited by 12 publications

(16 citation statements)

References 35 publications

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“…In addition to paramagnetic relaxation, further complications may arise when large amounts of paramagnetic metals are used because hyperfine interactions (scaler and dipolar) may shift and split the resonances, as seen in other chemical systems. 56 , 115 − 121 …”

Section: Resultsmentioning

confidence: 99%

Dynamic Nuclear Polarization of ¹H, ¹³C, and ⁵⁹Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

et al. 2014

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The study of inorganic crystalline materials by solid-state NMR spectroscopy is often complicated by the low sensitivity of heavy nuclei. However, these materials often contain or can be prepared with paramagnetic dopants without significantly affecting the structure of the crystalline host. Dynamic nuclear polarization (DNP) is generally capable of enhancing NMR signals by transferring the magnetization of unpaired electrons to the nuclei. Therefore, the NMR sensitivity in these paramagnetically doped crystals might be increased by DNP. In this paper we demonstrate the possibility of efficient DNP transfer in polycrystalline samples of [Co(en)3Cl3]2·NaCl·6H2O (en = ethylenediamine, C2H8N2) doped with Cr(III) in varying concentrations between 0.1 and 3 mol %. We demonstrate that 1H, 13C, and 59Co can be polarized by irradiation of Cr(III) with 140 GHz microwaves at a magnetic field of 5 T. We further explain our findings on the basis of electron paramagnetic resonance spectroscopy of the Cr(III) site and analysis of its temperature-dependent zero-field splitting, as well as the dependence of the DNP enhancement factor on the external magnetic field and microwave power. This first demonstration of DNP transfer from one paramagnetic metal ion to its diamagnetic host metal ion will pave the way for future applications of DNP in paramagnetically doped materials or metalloproteins.

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Section: Resultsmentioning

confidence: 99%

Dynamic Nuclear Polarization of ¹H, ¹³C, and ⁵⁹Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

et al. 2014

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“…and its receptivity, a change in the surrounding eight B″(Ag)/ B′(In or Bi) neighbors in the parent materials (i.e., an antisite defect) should induce a new resonance as the alloying discussed above shows. Considering that a spinning side band at <1% intensity is detectable, we predict a new Cs chemical environment induced by an antisite defect would be observed in the parent133 Cs NMR spectra if present at ∼0.15% as each B site substitution would impact eight neighboring Cs sites in the extended unit cell 71. This is further supported by the very small quadrupole coupling constants for the209 Bi and115 In parent compounds where only a few firstorder spinning side bands are observed from the satellite transitions and the PXRD (above), suggesting minimal intrinsic defects in these materials.…”

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confidence: 96%

Tailorable Indirect to Direct Band-Gap Double Perovskites with Bright White-Light Emission: Decoding Chemical Structure Using Solid-State NMR

et al. 2020

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Efficient white-light-emitting single-material sources are ideal for sustainable lighting applications. Though layered hybrid lead−halide perovskite materials have demonstrated attractive broadband white-light emission properties, they pose a serious long-term environmental and health risk as they contain lead (Pb 2+ ) and are readily soluble in water. Recently, lead-free halide double perovskite (HDP) materials with a generic formula A(I) 2 B′(III)B″(I)X 6 (where A and B are cations and X is a halide ion) have demonstrated whitelight emission with improved photoluminescence quantum yields (PLQYs). Here, we present a series of Bi 3+ /In 3+ mixed-cationic Cs 2 Bi 1−x In x AgCl 6 HDP solid solutions that span the indirect to direct band-gap modification which exhibit tailorable optical properties. Density functional theory (DFT) calculations indicate an indirect− direct band-gap crossover composition when x > 0.50. These HDP materials emit over the entire visible light spectrum, centered at 600 ± 30 nm with full-width at half maxima of ca. 200 nm upon ultraviolet light excitation and a maximum PLQY of 34 ± 4% for Cs 2 Bi 0.085 In 0.915 AgCl 6 . Short-range structural insight for these materials is crucial to unravel the unique atomic-level structural properties which are difficult to distinguish by diffraction-based techniques. Hence, we demonstrate the advantage of using solid-state nuclear magnetic resonance (NMR) spectroscopy to deconvolute the local structural environments of these mixed-cationic HDPs. Using ultrahigh-field (21.14 T) NMR spectroscopy of quadrupolar nuclei ( 115 In, 133 Cs, and 209 Bi), we show that there is a high degree of atomic-level B′(III)/B″(I) site ordering (i.e., no evidence of antisite defects). Furthermore, a combination of XRD, NMR, and DFT calculations was used to unravel the complete atomic-level random Bi 3+ /In 3+ cationic mixing in Cs 2 Bi 1−x In x AgCl 6 HDPs. Briefly, this work provides an advance in understanding the photophysical properties that correlate long-to short-range structural elucidation of these newly developed solid-state white-light emitting HDP materials.

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“…The applications of MAS NMR to paramagnetic systems encompass analysis of biological systems 11,89,90 as well as numerous inorganic materials. 87,91–93 …”

Section: Contemporary Advances In Mas Nmr Instrumentation and Methodomentioning

confidence: 99%

Magic Angle Spinning NMR Spectroscopy: A Versatile Technique for Structural and Dynamic Analysis of Solid-Phase Systems

2015

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Magic Angle Spinning (MAS) NMR spectroscopy is a powerful method for analysis of a broad range of systems, including inorganic materials, pharmaceuticals, and biomacromolecules. The recent developments in MAS NMR instrumentation and methodologies opened new vistas to atomic-level characterization of a plethora of chemical environments previously inaccessible to analysis, with unprecedented sensitivity and resolution.

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Determining Electron Spin-Transfer Mechanisms in Paramagnetic Ba₂YMO₆ (M = Mo, Re, Ru) Double Perovskites by ⁸⁹Y and ¹³⁷Ba MAS NMR Spectroscopy

Cited by 12 publications

References 35 publications

Dynamic Nuclear Polarization of ¹H, ¹³C, and ⁵⁹Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

Dynamic Nuclear Polarization of ¹H, ¹³C, and ⁵⁹Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

Tailorable Indirect to Direct Band-Gap Double Perovskites with Bright White-Light Emission: Decoding Chemical Structure Using Solid-State NMR

Magic Angle Spinning NMR Spectroscopy: A Versatile Technique for Structural and Dynamic Analysis of Solid-Phase Systems

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Determining Electron Spin-Transfer Mechanisms in Paramagnetic Ba2YMO6 (M = Mo, Re, Ru) Double Perovskites by 89Y and 137Ba MAS NMR Spectroscopy

Cited by 12 publications

References 35 publications

Dynamic Nuclear Polarization of 1H, 13C, and 59Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

Dynamic Nuclear Polarization of 1H, 13C, and 59Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

Tailorable Indirect to Direct Band-Gap Double Perovskites with Bright White-Light Emission: Decoding Chemical Structure Using Solid-State NMR

Magic Angle Spinning NMR Spectroscopy: A Versatile Technique for Structural and Dynamic Analysis of Solid-Phase Systems

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Determining Electron Spin-Transfer Mechanisms in Paramagnetic Ba₂YMO₆ (M = Mo, Re, Ru) Double Perovskites by ⁸⁹Y and ¹³⁷Ba MAS NMR Spectroscopy

Dynamic Nuclear Polarization of ¹H, ¹³C, and ⁵⁹Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)

Dynamic Nuclear Polarization of ¹H, ¹³C, and ⁵⁹Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)