1
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Roth AN, Chen Y, Santhiran A, Opare-Addo J, Gi E, Smith EA, Rossini AJ, Vela J. Designing complex Pb 3SBr xI 4-x chalcohalides: tunable emission semiconductors through halide-mixing. Chem Sci 2023; 14:12331-12338. [PMID: 37969605 PMCID: PMC10631247 DOI: 10.1039/d3sc02733c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/12/2023] [Indexed: 11/17/2023] Open
Abstract
Chalcohalides are desirable semiconducting materials due to their enhanced light-absorbing efficiency and stability compared to lead halide perovskites. However, unlike perovskites, tuning the optical properties of chalcohalides by mixing different halide ions into their structure remains to be explored. Here, we present an effective strategy for halide-alloying Pb3SBrxI4-x (1 ≤ x ≤ 3) using a solution-phase approach and study the effect of halide-mixing on structural and optical properties. We employ a combination of X-ray diffraction, electron microscopy, and solid-state NMR spectroscopy to probe the chemical structure of the chalcohalides and determine mixed-halide incorporation. The absorption onsets of the chalcohalides blue-shift to higher energies as bromide replaces iodide within the structure. The photoluminescence maxima of these materials mimics this trend at both the ensemble and single particle fluorescence levels, as observed by solution-phase and single particle fluorescence microscopy, respectively. These materials exhibit superior stability against moisture compared to traditional lead halide perovskites, and IR spectroscopy reveals that the chalcohalide surfaces are terminated by both amine and carboxylate ligands. Electronic structure calculations support the experimental band gap widening and volume reduction with increased bromide incorporation, and provide useful insight into the likely atomic coloring patterns of the different mixed-halide compositions. Ultimately, this study expands the range of tunability that is achievable with chalcohalides, which we anticipate will improve the suitability of these semiconducting materials for light absorbing and emission applications.
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Affiliation(s)
- Alison N Roth
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
| | - Yunhua Chen
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
| | - Anuluxan Santhiran
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
| | - Jemima Opare-Addo
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
| | - Eunbyeol Gi
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
| | - Emily A Smith
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
| | - Aaron J Rossini
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
| | - Javier Vela
- US DOE Ames National Laboratory Ames Iowa 50010 USA
- Department of Chemistry, Iowa State University Ames Iowa 50011 USA
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2
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Bulk and Nanoscale Semiconducting Materials: Structural Advances Using Solid-state NMR Spectroscopy. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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3
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Roth AN, Chen Y, Adamson MAS, Gi E, Wagner M, Rossini AJ, Vela J. Alkaline-Earth Chalcogenide Nanocrystals: Solution-Phase Synthesis, Surface Chemistry, and Stability. ACS NANO 2022; 16:12024-12035. [PMID: 35849721 DOI: 10.1021/acsnano.2c02116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Increasing demand for effective energy conversion materials and devices has renewed interest in semiconductors comprised of earth-abundant and biocompatible elements. Alkaline-earth sulfides doped with rare earth ions are versatile optical materials. However, relatively little is known about controlling the dimensionality, surface chemistry, and inherent optical properties of the undoped versions of alkaline-earth mono- and polychalcogenides. We describe the colloidal synthesis of alkaline-earth chalcogenide nanocrystals through the reaction of metal carboxylates with carbon disulfide or selenourea. Systematic exploration of the synthetic phase space allows us to tune particle sizes over a wide range using a mixture of commercially available carboxylate precursors. Solid-state NMR spectroscopy confirms the phase purity of the selenide compositions. Surface characterization reveals that bridging carboxylates and amines preferentially terminate the surface of the nanocrystals. While these materials are colloidally stable in the mother solution, the selenides are susceptible to oxidation over time, eventually degrading to selenium metal through polyselenide intermediates. As part of these investigations, we have developed the colloidal syntheses of barium di- and triselenides, two among few reported nanocrystalline alkaline-earth polychalcogenides. Electronic structure calculations reveal that both materials are indirect band gap semiconductors. The colloidal chemistry presented here may enable the synthesis of more complex, multinary chalcogenide materials containing alkaline-earth elements.
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Affiliation(s)
- Alison N Roth
- US DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Yunhua Chen
- US DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Marquix A S Adamson
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Eunbyeol Gi
- US DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Molly Wagner
- US DOE Ames Laboratory, Ames, Iowa 50011, United States
| | - Aaron J Rossini
- US DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Javier Vela
- US DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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4
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NMR spectroscopy probes microstructure, dynamics and doping of metal halide perovskites. Nat Rev Chem 2021; 5:624-645. [PMID: 37118421 DOI: 10.1038/s41570-021-00309-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2021] [Indexed: 12/23/2022]
Abstract
Solid-state magic-angle spinning NMR spectroscopy is a powerful technique to probe atomic-level microstructure and structural dynamics in metal halide perovskites. It can be used to measure dopant incorporation, phase segregation, halide mixing, decomposition pathways, passivation mechanisms, short-range and long-range dynamics, and other local properties. This Review describes practical aspects of recording solid-state NMR data on halide perovskites and how these afford unique insights into new compositions, dopants and passivation agents. We discuss the applicability, feasibility and limitations of 1H, 13C, 15N, 14N, 133Cs, 87Rb, 39K, 207Pb, 119Sn, 113Cd, 209Bi, 115In, 19F and 2H NMR in typical experimental scenarios. We highlight the pivotal complementary role of solid-state mechanosynthesis, which enables highly sensitive NMR studies by providing large quantities of high-purity materials of arbitrary complexity and of chemical shifts calculated using density functional theory. We examine the broader impact of solid-state NMR on materials research and how its evolution over seven decades has benefitted structural studies of contemporary materials such as halide perovskites. Finally, we summarize some of the open questions in perovskite optoelectronics that could be addressed using solid-state NMR. We, thereby, hope to stimulate wider use of this technique in materials and optoelectronics research.
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5
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Chen Y, Dorn RW, Hanrahan MP, Wei L, Blome-Fernández R, Medina-Gonzalez AM, Adamson MAS, Flintgruber AH, Vela J, Rossini AJ. Revealing the Surface Structure of CdSe Nanocrystals by Dynamic Nuclear Polarization-Enhanced 77Se and 113Cd Solid-State NMR Spectroscopy. J Am Chem Soc 2021; 143:8747-8760. [PMID: 34085812 DOI: 10.1021/jacs.1c03162] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dynamic nuclear polarization (DNP) solid-state NMR (SSNMR) spectroscopy was used to obtain detailed surface structures of zinc blende CdSe nanocrystals (NCs) with plate or spheroidal morphologies which are capped by carboxylic acid ligands. 1D 113Cd and 77Se cross-polarization magic angle spinning (CPMAS) NMR spectra revealed distinct signals from Cd and Se atoms on the surface of the NCs, and those residing in bulk-like environments, below the surface. 113Cd cross-polarization magic-angle-turning (CP-MAT) experiments identified CdSe3O, CdSe2O2, and CdSeO3 Cd coordination environments on the surface of the NCs, where the oxygen atoms are presumably from coordinated carboxylate ligands. The sensitivity gain from DNP enabled natural isotopic abundance 2D homonuclear 113Cd-113Cd and 77Se-77Se and heteronuclear 113Cd-77Se scalar correlation solid-state NMR experiments which revealed the connectivity of the Cd and Se atoms. Importantly, 77Se{113Cd} scalar heteronuclear multiple quantum coherence (J-HMQC) experiments were used to selectively measure one-bond 77Se-113Cd scalar coupling constants (1J(77Se, 113Cd)). With knowledge of 1J(77Se, 113Cd), heteronuclear 77Se{113Cd} spin echo (J-resolved) NMR experiments were used to determine the number of Cd atoms bonded to Se atoms and vice versa. The J-resolved experiments directly confirmed that major Cd and Se surface species have CdSe2O2 and SeCd4 stoichiometries, respectively. Considering the crystal structure of zinc blende CdSe and the similarity of the solid-state NMR data for the platelets and spheroids, we conclude that the surface of the spheroidal CdSe NCs is primarily composed of {100} facets. The methods outlined here will generally be applicable to obtain detailed surface structures of various main group semiconductor nanoparticles.
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Affiliation(s)
- Yunhua Chen
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Rick W Dorn
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Michael P Hanrahan
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Lin Wei
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | | | | | - Marquix A S Adamson
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Anne H Flintgruber
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States
| | - Javier Vela
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Aaron J Rossini
- U.S. Department of Energy Ames Laboratory, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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6
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Xing B, Ge S, Zhao J, Yang H, Song J, Geng Y, Qiao Y, Gu L, Han P, Ma G. Alloyed Crystalline CdSe 1-xS x Semiconductive Nanomaterials - A Solid State 113Cd NMR Study. ChemistryOpen 2020; 9:1018-1026. [PMID: 33072471 PMCID: PMC7549000 DOI: 10.1002/open.202000216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/03/2020] [Indexed: 01/14/2023] Open
Abstract
Solid‐state NMR analysis on wurtzite alloyed CdSe1−xSx crystalline nanoparticles and nanobelts provides evidence that the 113Cd NMR chemical shift is not affected by the varying sizes of nanoparticles, but is sensitive to the S/Se anion molar ratios. A linear correlation is observed between 113Cd NMR chemical shifts and the sulfur component for the alloyed CdSe1−xSx (0<x<1) system both in nanoparticles and nanobelts (δCd=169.71⋅XS+529.21). Based on this correlation, a rapid and applied approach has been developed to determine the composition of the alloyed nanoscalar materials utilizing 113Cd NMR spectroscopy. The observed results from this system confirm that one can use 113Cd NMR spectroscopy not only to determine the composition but also the phase separation of nanomaterial semiconductors without destruction of the sample structures. In addition, some observed correlations are discussed in detail.
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Affiliation(s)
- Baoyan Xing
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.,Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Sai Ge
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Jianguo Zhao
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.,Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Hui Yang
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Jie Song
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Yu Geng
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Yuying Qiao
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Ling Gu
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
| | - Peide Han
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Guibin Ma
- Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China
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7
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Guo H, Jaworski A, Ma Z, Slabon A, Bacsik Z, Nedumkandathil R, Häussermann U. Trapping of different stages of BaTiO 3 reduction with LiH. RSC Adv 2020; 10:35356-35365. [PMID: 35515653 PMCID: PMC9056924 DOI: 10.1039/d0ra07276a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 09/15/2020] [Indexed: 11/21/2022] Open
Abstract
We investigated the hydride reduction of tetragonal BaTiO3 using LiH. The reactions employed molar H : BaTiO3 ratios of 1.2, 3, and 10 and variable temperatures up to 700 °C. The air-stable reduced products were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy, thermogravimetric analysis (TGA), X-ray fluorescence (XRF), and 1H magic-angle spinning (MAS) NMR spectroscopy. Effective reduction, as indicated by the formation of dark blue to black colored, cubic-phased, products was observed at temperatures as low as 300 °C. The product obtained at 300 °C corresponded to oxyhydride BaTiO∼2.9H∼0.1, whereas reduction at higher temperatures resulted in simultaneous O defect formation, BaTiO2.9-x H0.1□ x , and eventually - at temperatures above 450 °C - to samples void of hydridic H. Concomitantly, the particles of samples reduced at high temperatures (500-600 °C) display substantial surface alteration, which is interpreted as the formation of a TiO x (OH) y shell, and sintering. Diffuse reflectance UV-VIS spectroscopy shows broad absorption in the VIS-NIR region, which is indicative of the presence of n-type free charge carriers. The size of the intrinsic band gap (∼3.2 eV) appears only slightly altered. Mott-Schottky measurements confirm the n-type conductivity and reveal shifts of the conduction band edge in the LiH reduced samples. Thus LiH appears as a versatile reagent to produce various distinct forms of reduced BaTiO3 with tailored electronic properties.
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Affiliation(s)
- Hua Guo
- Department of Materials and Environmental Chemistry, Stockholm University SE-10691 Stockholm Sweden
| | - Aleksander Jaworski
- Department of Materials and Environmental Chemistry, Stockholm University SE-10691 Stockholm Sweden
| | - Zili Ma
- Department of Materials and Environmental Chemistry, Stockholm University SE-10691 Stockholm Sweden .,Institute of Inorganic Chemistry, RWTH Aachen University Landoltweg 1 DE-52074 Aachen Germany
| | - Adam Slabon
- Department of Materials and Environmental Chemistry, Stockholm University SE-10691 Stockholm Sweden
| | - Zoltan Bacsik
- Department of Materials and Environmental Chemistry, Stockholm University SE-10691 Stockholm Sweden
| | - Reji Nedumkandathil
- Department of Materials and Environmental Chemistry, Stockholm University SE-10691 Stockholm Sweden
| | - Ulrich Häussermann
- Department of Materials and Environmental Chemistry, Stockholm University SE-10691 Stockholm Sweden
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8
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Chen Y, Smock SR, Flintgruber AH, Perras FA, Brutchey RL, Rossini AJ. Surface Termination of CsPbBr3 Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy. J Am Chem Soc 2020; 142:6117-6127. [DOI: 10.1021/jacs.9b13396] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Yunhua Chen
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Sara R. Smock
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | | | | | - Richard L. Brutchey
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Aaron J. Rossini
- U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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9
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Pell AJ, Pintacuda G, Grey CP. Paramagnetic NMR in solution and the solid state. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 111:1-271. [PMID: 31146806 DOI: 10.1016/j.pnmrs.2018.05.001] [Citation(s) in RCA: 215] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 05/11/2018] [Accepted: 05/12/2018] [Indexed: 05/22/2023]
Abstract
The field of paramagnetic NMR has expanded considerably in recent years. This review addresses both the theoretical description of paramagnetic NMR, and the way in which it is currently practised. We provide a review of the theory of the NMR parameters of systems in both solution and the solid state. Here we unify the different languages used by the NMR, EPR, quantum chemistry/DFT, and magnetism communities to provide a comprehensive and coherent theoretical description. We cover the theory of the paramagnetic shift and shift anisotropy in solution both in the traditional formalism in terms of the magnetic susceptibility tensor, and using a more modern formalism employing the relevant EPR parameters, such as are used in first-principles calculations. In addition we examine the theory first in the simple non-relativistic picture, and then in the presence of spin-orbit coupling. These ideas are then extended to a description of the paramagnetic shift in periodic solids, where it is necessary to include the bulk magnetic properties, such as magnetic ordering at low temperatures. The description of the paramagnetic shift is completed by describing the current understanding of such shifts due to lanthanide and actinide ions. We then examine the paramagnetic relaxation enhancement, using a simple model employing a phenomenological picture of the electronic relaxation, and again using a more complex state-of-the-art theory which incorporates electronic relaxation explicitly. An additional important consideration in the solid state is the impact of bulk magnetic susceptibility effects on the form of the spectrum, where we include some ideas from the field of classical electrodynamics. We then continue by describing in detail the solution and solid-state NMR methods that have been deployed in the study of paramagnetic systems in chemistry, biology, and the materials sciences. Finally we describe a number of case studies in paramagnetic NMR that have been specifically chosen to highlight how the theory in part one, and the methods in part two, can be used in practice. The systems chosen include small organometallic complexes in solution, solid battery electrode materials, metalloproteins in both solution and the solid state, systems containing lanthanide ions, and multi-component materials used in pharmaceutical controlled-release formulations that have been doped with paramagnetic species to measure the component domain sizes.
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Affiliation(s)
- Andrew J Pell
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Svante Arrhenius väg 16 C, SE-106 91 Stockholm, Sweden.
| | - Guido Pintacuda
- Institut des Sciences Analytiques (CNRS UMR 5280, ENS de Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Clare P Grey
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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10
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Tansho M, Suehiro T, Shimizu T. Constancy of the quadrupolar interaction product in nanocrystalline gallium nitride revealed by 71Ga MAS NMR shift distribution. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 97:25-30. [PMID: 30583084 DOI: 10.1016/j.ssnmr.2018.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 08/01/2018] [Accepted: 08/01/2018] [Indexed: 06/09/2023]
Abstract
The question of whether the broad 71,69Ga nuclear magnetic resonance (NMR) signal of hexagonal gallium nitride (h-GaN) at 530-330 ppm is related to the Knight shift (caused by the presence of carriers in semiconductors) is the subject of intense debate. The intensity increase observed for the narrower 71Ga magic angle spinning (MAS) NMR signals above 1050 °C suggests that the broader signals do not reflect the decomposition of h-GaN. Herein, we utilized 71Ga multi-quantum (MQ) MAS NMR spectroscopy to reveal that the quadrupolar interaction products for the broad signal of nanocrystalline h-GaN are almost constant in the entire shift range that we investigated, equaling 1.7 ± 0.1 MHz or similar values. Since the above parameter is sensitive to the local chemical symmetry around the Ga atom, the NMR shift distribution is considered not to be related to that of the chemical environment. Consistent with the most recent reports, including those on double-resonance 15N{71Ga} measurements, the Knight shift may be ascribed to defects serving as shallow donors and populating the conduction band. Thus, MQMAS measurements performed using a low-field NMR instrument or by choosing half-integer quadrupole nuclei with a large quadrupole constant such as 69Ga are expected to provide important information for each Knight shift value and for analyzing the nature of semiconductors other than GaN.
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Affiliation(s)
- Masataka Tansho
- High Field NMR Group, Research Center for Advanced Measurement and Characterization, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, 305-0003, Japan.
| | - Takayuki Suehiro
- Sialon Group, Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Tadashi Shimizu
- High Field NMR Group, Research Center for Advanced Measurement and Characterization, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, 305-0003, Japan
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11
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Nedumkandathil R, Jaworski A, Grins J, Bernin D, Karlsson M, Eklöf-Österberg C, Neagu A, Tai CW, Pell AJ, Häussermann U. Hydride Reduction of BaTiO 3 - Oxyhydride Versus O Vacancy Formation. ACS OMEGA 2018; 3:11426-11438. [PMID: 31459246 PMCID: PMC6645482 DOI: 10.1021/acsomega.8b01368] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/29/2018] [Indexed: 06/09/2023]
Abstract
We investigated the hydride reduction of tetragonal BaTiO3 using the metal hydrides CaH2, NaH, MgH2, NaBH4, and NaAlH4. The reactions employed molar BaTiO3/H ratios of up to 1.8 and temperatures near 600 °C. The air-stable reduced products were characterized by powder X-ray diffraction (PXRD), transmission electron microscopy, thermogravimetric analysis (TGA), and 1H magic angle spinning (MAS) NMR spectroscopy. PXRD showed the formation of cubic products-indicative of the formation of BaTiO3-x H x -except for NaH. Lattice parameters were in a range between 4.005 Å (for NaBH4-reduced samples) and 4.033 Å (for MgH2-reduced samples). With increasing H/BaTiO3 ratio, CaH2-, NaAlH4-, and MgH2-reduced samples were afforded as two-phase mixtures. TGA in air flow showed significant weight increases of up to 3.5% for reduced BaTiO3, suggesting that metal hydride reduction yielded oxyhydrides BaTiO3-x H x with x values larger than 0.5. 1H MAS NMR spectroscopy, however, revealed rather low concentrations of H and thus a simultaneous presence of O vacancies in reduced BaTiO3. It has to be concluded that hydride reduction of BaTiO3 yields complex disordered materials BaTiO3-x H y □(x-y) with x up to 0.6 and y in a range 0.04-0.25, rather than homogeneous solid solutions BaTiO3-x H x . Resonances of (hydridic) H substituting O in the cubic perovskite structure appear in the -2 to -60 ppm spectral region. The large range of negative chemical shifts and breadth of the signals signifies metallic conductivity and structural disorder in BaTiO3-x H y □(x-y). Sintering of BaTiO3-x H y □(x-y) in a gaseous H2 atmosphere resulted in more ordered materials, as indicated by considerably sharper 1H resonances.
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Affiliation(s)
- Reji Nedumkandathil
- Department
of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
| | - Aleksander Jaworski
- Department
of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
| | - Jekabs Grins
- Department
of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
| | - Diana Bernin
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-41296 Gothenburg, Sweden
| | - Maths Karlsson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-41296 Gothenburg, Sweden
| | - Carin Eklöf-Österberg
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, SE-41296 Gothenburg, Sweden
| | - Alexandra Neagu
- Department
of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
| | - Cheuk-Wai Tai
- Department
of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
| | - Andrew J. Pell
- Department
of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
| | - Ulrich Häussermann
- Department
of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
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12
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Levchenko TI, Lucier BEG, Corrigan JF, Huang Y. Crystalline Superlattices of Nanoscopic CdS Molecular Clusters: An X-ray Crystallography and 111Cd SSNMR Spectroscopy Study. Inorg Chem 2018; 57:204-217. [PMID: 29243923 DOI: 10.1021/acs.inorgchem.7b02403] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Systematic 111Cd solid-state (SS) NMR experiments were performed to correlate X-ray crystallographic data with SSNMR parameters for a set of CdS-based materials, varying from molecular crystals of small complexes [Cd(SPh)4]2- and [Cd4(SPh)10]2- to superlattices of large monodisperse clusters [Cd54S32(SPh)48(dmf)4]4- and 1.9 nm CdS. Methodical data analysis allowed for assigning individual resonances or resonance groups to particular types of cadmium sites residing in different chemical and/or crystallographic environments. For large CdS frameworks, 111Cd resonances were found to form three groups. This result is noteworthy, since for related systems with size polydispersity and variations in composition, such as CdS or CdSe nanoparticles protected with an organic ligand shell, typically only two groups of resonances were observed. The generalized information obtained in this work can be used for the interpretation of 111/113Cd SSNMR data for large CdS clusters and nanoparticles, for which crystal structure analysis remains inaccessible. Comparison of the powder X-ray diffraction patterns for freshly prepared and dried superlattices of large CdS clusters revealed an interesting superstructure rearrangement that was not observed for the smaller frameworks.
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Affiliation(s)
- Tetyana I Levchenko
- Department of Chemistry and ‡The Centre for Advanced Materials and Biomaterials Research, The University of Western Ontario , London, Ontario N6A 5B7, Canada
| | - Bryan E G Lucier
- Department of Chemistry and ‡The Centre for Advanced Materials and Biomaterials Research, The University of Western Ontario , London, Ontario N6A 5B7, Canada
| | - John F Corrigan
- Department of Chemistry and ‡The Centre for Advanced Materials and Biomaterials Research, The University of Western Ontario , London, Ontario N6A 5B7, Canada
| | - Yining Huang
- Department of Chemistry and ‡The Centre for Advanced Materials and Biomaterials Research, The University of Western Ontario , London, Ontario N6A 5B7, Canada
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13
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Willmering MM, Ma ZL, Jenkins MA, Conley JF, Hayes SE. Enhanced NMR with Optical Pumping Yields 75As Signals Selectively from a Buried GaAs Interface. J Am Chem Soc 2017; 139:3930-3933. [PMID: 28256125 DOI: 10.1021/jacs.6b08970] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have measured the 75As signals arising from the interface region of single-crystal semi-insulating GaAs that has been coated and passivated with an aluminum oxide film deposited by atomic layer deposition (ALD) with optically pumped NMR (OPNMR). Using wavelength-selective optical pumping, the laser restricts the volume from which OPNMR signals are collected. Here, OPNMR signals were obtained from the interface region and distinguished from signals arising from the bulk. The interface region is highlighted by interactions that disrupt the cubic symmetry of the GaAs lattice, resulting in quadrupolar satellites for nuclear [Formula: see text] isotopes, whereas NMR of the "bulk" lattice is nominally unsplit. Quadrupolar splitting at the interface arises from strain based on lattice mismatch between the GaAs and ALD-deposited aluminum oxide due to their different coefficients of thermal expansion. Such spectroscopic evidence of strain can be useful for measuring lattice distortions at heterojunction boundaries and interfaces.
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Affiliation(s)
- Matthew M Willmering
- Department of Chemistry, Washington University , Saint Louis, Missouri 63130, United States
| | - Zayd L Ma
- Department of Chemistry, Washington University , Saint Louis, Missouri 63130, United States
| | - Melanie A Jenkins
- School of Electrical Engineering and Computer Science, Oregon State University , Corvallis, Oregon 97331, United States
| | - John F Conley
- School of Electrical Engineering and Computer Science, Oregon State University , Corvallis, Oregon 97331, United States
| | - Sophia E Hayes
- Department of Chemistry, Washington University , Saint Louis, Missouri 63130, United States
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14
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Knijn PJ, van Bentum PJM, Fang CM, Bauhuis GJ, de Wijs GA, Kentgens APM. A multi-nuclear magnetic resonance and density functional theory investigation of epitaxially grown InGaP 2. Phys Chem Chem Phys 2016; 18:21296-304. [DOI: 10.1039/c5cp04593b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NMR spectra of InGaP2, dependent on coordination and disorder. Experimental (left) and DFT modelling (right).
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Affiliation(s)
- P. J. Knijn
- Radboud University
- Institute for Molecules and Materials
- NL-6525 AJ Nijmegen
- The Netherlands
| | - P. J. M. van Bentum
- Radboud University
- Institute for Molecules and Materials
- NL-6525 AJ Nijmegen
- The Netherlands
| | - C. M. Fang
- Radboud University
- Institute for Molecules and Materials
- NL-6525 AJ Nijmegen
- The Netherlands
| | - G. J. Bauhuis
- Radboud University
- Institute for Molecules and Materials
- NL-6525 AJ Nijmegen
- The Netherlands
| | - G. A. de Wijs
- Radboud University
- Institute for Molecules and Materials
- NL-6525 AJ Nijmegen
- The Netherlands
| | - A. P. M. Kentgens
- Radboud University
- Institute for Molecules and Materials
- NL-6525 AJ Nijmegen
- The Netherlands
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15
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Piveteau L, Ong TC, Rossini AJ, Emsley L, Copéret C, Kovalenko MV. Structure of Colloidal Quantum Dots from Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy. J Am Chem Soc 2015; 137:13964-71. [PMID: 26473384 DOI: 10.1021/jacs.5b09248] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the chemistry of colloidal quantum dots (QDs) is primarily hampered by the lack of analytical methods to selectively and discriminately probe the QD core, QD surface and capping ligands. Here, we present a general concept for studying a broad range of QDs such as CdSe, CdTe, InP, PbSe, PbTe, CsPbBr3, etc., capped with both organic and inorganic surface capping ligands, through dynamic nuclear polarization (DNP) surface enhanced NMR spectroscopy. DNP can enhance NMR signals by factors of 10-100, thereby reducing the measurement times by 2-4 orders of magnitude. 1D DNP enhanced spectra acquired in this way are shown to clearly distinguish QD surface atoms from those of the QD core, and environmental effects such as oxidation. Furthermore, 2D NMR correlation experiments, which were previously inconceivable for QD surfaces, are demonstrated to be readily performed with DNP and provide the bonding motifs between the QD surfaces and the capping ligands.
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Affiliation(s)
- Laura Piveteau
- Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - Ta-Chung Ong
- Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
| | - Aaron J Rossini
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015, Switzerland
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland
| | - Maksym V Kovalenko
- Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir Prelog Weg 1-5, Zürich CH-8093, Switzerland.,Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, Dübendorf CH-8600, Switzerland
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16
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Yesinowski JP. Finding the true spin-lattice relaxation time for half-integral nuclei with non-zero quadrupole couplings. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 252:135-144. [PMID: 25700115 DOI: 10.1016/j.jmr.2014.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/17/2014] [Accepted: 12/23/2014] [Indexed: 06/04/2023]
Abstract
Measuring true spin-lattice relaxation times T(1) of half-integral quadrupolar nuclei having non-zero nuclear quadrupole coupling constants (NQCCs) presents challenges due to the presence of satellite-transitions (STs) that may lie outside the excitation bandwidth of the central transition (CT). This leads to complications in establishing well-defined initial conditions for the population differences in these multi-level systems. In addition, experiments involving magic-angle spinning (MAS) can introduce spin exchange due to zero-crossings of the ST and CT (or possibly rotational resonance recoupling in the case of multiple sites) and greatly altered initial conditions as well. An extensive comparison of pulse sequences that have been previously used to measure T(1) in such systems is reported, using the (71)Ga (I=3/2) NMR of a Ge-doped h-GaN n-type semiconductor sample as the test case. The T(1) values were measured at the peak maximum of the Knight shift distribution. Analytical expressions for magnetization-recovery of the CT appropriate to the pulse sequences tested were used, involving contributions from both a magnetic relaxation mechanism (rate constant W) and a quadrupolar one (rate constants W(1) and W(2), approximately equal in this case). An asynchronous train of high-power saturating pulses under MAS that is able to completely saturate both CT and STs is found to be the most reliable and accurate method for obtaining the "true T(1)", defined here as (2W+2W1,2)(-)(1). All other methods studied yielded poor agreement with this "true T(1)" value or even resulted in gross errors, for reasons that are analyzed in detail. These methods involved a synchronous train of saturating pulses under MAS, an inversion-recovery sequence under MAS or static conditions, and a saturating comb of pulses on a static sample. Although the present results were obtained on a sample where the magnetic relaxation mechanism dominated the quadrupolar one, the asynchronous saturating pulse train approach is not limited to this situation. The extent to which W(1) and W(2) are unequal does affect the interpretability of the experiment however, particularly when the quadrupolar mechanism dominates. A numerically approximate solution for the I=3/2 recovery case reveals the quantitative effects of any such inequality.
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Affiliation(s)
- James P Yesinowski
- Chemistry Division, Naval Research Laboratory, Washington, DC 20375-5342, USA.
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17
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Protesescu L, Rossini AJ, Kriegner D, Valla M, de Kergommeaux A, Walter M, Kravchyk KV, Nachtegaal M, Stangl J, Malaman B, Reiss P, Lesage A, Emsley L, Copéret C, Kovalenko MV. Unraveling the core-shell structure of ligand-capped Sn/SnOx nanoparticles by surface-enhanced nuclear magnetic resonance, Mössbauer, and X-ray absorption spectroscopies. ACS NANO 2014; 8:2639-48. [PMID: 24494636 DOI: 10.1021/nn406344n] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A particularly difficult challenge in the chemistry of nanomaterials is the detailed structural and chemical analysis of multicomponent nano-objects. This is especially true for the determination of spatially resolved information. In this study, we demonstrate that dynamic nuclear polarization surface-enhanced solid-state NMR spectroscopy (DNP-SENS), which provides selective and enhanced NMR signal collection from the (near) surface regions of a sample, can be used to resolve the core-shell structure of a nanoparticle. Li-ion anode materials, monodisperse 10-20 nm large tin nanoparticles covered with a ∼3 nm thick layer of native oxides, were used in this case study. DNP-SENS selectively enhanced the weak 119Sn NMR signal of the amorphous surface SnO2 layer. Mössbauer and X-ray absorption spectroscopies identified a subsurface SnO phase and quantified the atomic fractions of both oxides. Finally, temperature-dependent X-ray diffraction measurements were used to probe the metallic β-Sn core and indicated that even after 8 months of storage at 255 K there are no signs of conversion of the metallic β-Sn core into a brittle semiconducting α-phase, a phase transition which normally occurs in bulk tin at 286 K (13 °C). Taken together, these results indicate that Sn/SnOx nanoparticles have core/shell1/shell2 structure of Sn/SnO/SnO2 phases. The study suggests that DNP-SENS experiments can be carried on many types of uniform colloidal nanomaterials containing NMR-active nuclei, in the presence of either hydrophilic (ion-capped surfaces) or hydrophobic (capping ligands with long hydrocarbon chains) surface functionalities.
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Affiliation(s)
- Loredana Protesescu
- Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich CH-8093, Switzerland
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18
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Meintjes EM, Warren WW, Yesinowski JP. Temperature-dependent 29Si NMR resonance shifts in lightly- and heavily-doped Si:P. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 55-56:91-94. [PMID: 24183811 DOI: 10.1016/j.ssnmr.2013.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 10/01/2013] [Accepted: 10/04/2013] [Indexed: 06/02/2023]
Abstract
Careful NMR measurements on a very lightly-doped reference silicon sample provide a convenient highly precise and accurate secondary chemical shift reference standard for (29)Si MAS-NMR applicable over a wide temperature range. The linear temperature-dependence of the (29)Si chemical shift measured in this sample is used to refine an earlier presentation of the paramagnetic (high-frequency) (29)Si resonance shifts in heavily-doped n-type silicon samples near the metal-nonmetal transition. The data show systematic decreases of the local magnetic fields with increasing temperature in the range 100-470 K for all samples in the carrier concentration range from 2×10(18) cm(-3) to 8×10(19) cm(-3). This trend is qualitatively similar to that previously observed for the two-orders of magnitude larger (31)P impurity NMR resonance shifts in the same temperature and concentration ranges. The (29)Si and (31)P resonance shifts are not related by a simple scaling factor, however, indicating that impurity and host nuclei are affected by different subsets of partially-localized extrinsic electrons at all temperatures.
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Affiliation(s)
- Ernesta M Meintjes
- Department of Physics, Oregon State University, Corvallis, OR 97331-6501, USA
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19
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Gutmann T, Bonnefille E, Breitzke H, Debouttière PJ, Philippot K, Poteau R, Buntkowsky G, Chaudret B. Investigation of the surface chemistry of phosphine-stabilized ruthenium nanoparticles – an advanced solid-state NMR study. Phys Chem Chem Phys 2013; 15:17383-94. [DOI: 10.1039/c3cp52927d] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Hartman JS, Berno B, Hazendonk P, Hens P, Ye E, Bain AD. Spin-lattice relaxation in aluminum-doped semiconducting 4H and 6H polytypes of silicon carbide. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 45-46:45-50. [PMID: 22727848 DOI: 10.1016/j.ssnmr.2012.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 05/29/2012] [Accepted: 05/30/2012] [Indexed: 06/01/2023]
Abstract
NMR spin-lattice relaxation efficiency is similar at all carbon and silicon sites in aluminum-doped 4H- and 6H-polytype silicon carbide samples, indicating that the valence band edge (the top of the valence band), where the holes are located in p-doped materials, has similar charge densities at all atomic sites. This is in marked contrast to nitrogen-doped samples of the same polytypes where huge site-specific differences in relaxation efficiency indicate that the conduction band edge (the bottom of the conduction band), where the mobile electrons are located in n-doped materials, has very different charge densities at the different sites. An attempt was made to observe (27)Al NMR signals directly, but they are too broad, due to paramagnetic line broadening, to provide useful information about aluminum doping.
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Affiliation(s)
- J Stephen Hartman
- Department of Chemistry, Brock University, St. Catharines, Ontario, Canada.
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