scholarly journals Common Phase and Structure Misidentifications in High-Resolution TEM Characterization of Perovskite Materials

2020 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Yu-Hao Deng
Keyword(s):  
High Resolution ◽  
Research Field ◽  
Structure Characterization ◽  
Phase Identification ◽  
Lead Iodide ◽  
Perovskite Materials ◽  
High Resolution Tem ◽  
Methylammonium Lead Iodide ◽  
Dose Imaging

High-resolution TEM (HRTEM) is a powerful tool for structure characterization. However, methylammonium lead iodide (MAPbI3) perovskite is highly sensitive to electron beams and easily decomposes into lead iodide (PbI2). Misidentifications, such as PbI2 being incorrectly labeled as perovskite, are widely present in HRTEM characterization and would negatively affect the development of perovskite research field. Here misidentifications in MAPbI3 perovskite are summarized, classified, and corrected based on low-dose imaging and electron diffraction (ED) simulations. Corresponding crystallographic parameters of intrinsic tetragonal MAPbI3 and the confusable hexagonal PbI2 are presented unambiguously. Finally, the method of proper phase identification and some strategies to control the radiation damage in HRTEM are provided. This warning paves the way to avoid future misinterpretations in HRTEM characterization of perovskite and other electron beam-sensitive materials.

High-resolution electron microscopy on SSZ-26 zeolite materials

1991 ◽  
Vol 49 ◽  
pp. 1032-1033 ◽  
Author(s):  
M. Pan ◽  
P.A. Crozier ◽  
I.Y. Chan ◽  
S.I. Zones
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Imaging Techniques ◽  
High Resolution Electron Microscopy ◽  
Shape Selectivity ◽  
Structure Characterization ◽  
Resolution Electron ◽  
Structure Sensitive ◽  
Dose Imaging

Zeolites constitute an important class of catalyst materials in the petrochemical industry. Zeolites are aluminosilicates with their framework structures made up of SiO4 (or AlO4) tetrahedra. The catalytic properties such as selectivity and activity are closely related to the structure sensitive properties of zeolites, e.g. shape selectivity, diffusivity, etc. Understanding these properties requires detailed structure characterization of the zeolites. High resolution electron microscopy (HREM) has been successfully applied to solve some zeolite structures when combined with experimental data from other techniques, e.g. absorption experiment. The connectivities of n-member rings in the zeolite frameworks can be directly deduced from the corresponding HREM images. However, radiation damage to the zeolite framework structures by the electron beam necessitates the use of low dose imaging techniques.

scholarly journals Transmission electron microscopy as an important tool for characterization of zeolite structures

2018 ◽  
Vol 5 (11) ◽  
pp. 2836-2855 ◽  
Author(s):  
W. Wan ◽  
J. Su ◽  
X. D. Zou ◽  
T. Willhammar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Electron Tomography ◽  
Structure Characterization ◽  
Transmission Electron ◽  
High Resolution Tem

This review presents various TEM techniques including electron diffraction, high-resolution TEM and scanning TEM imaging, and electron tomography and their applications for structure characterization of zeolite materials.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Structural Characterization of Epitaxial GMR Magnetic Multilayers and Spin Valves Grown by Sputter Deposition

2000 ◽  
Vol 614 ◽  
Author(s):  
H. Geng ◽  
R. Loloee ◽  
J.W. Heckman ◽  
J. Bass ◽  
W.P. Pratt ◽  
...  
Keyword(s):  
High Resolution ◽  
Epitaxial Growth ◽  
Magnetic Multilayers ◽  
Sputter Deposition ◽  
Dc Magnetron Sputtering ◽  
Cu Films ◽  
Electron Backscatter ◽  
High Resolution Tem ◽  
Fcc Structure

ABSTRACTEpitaxial Cu/Py/FeMn and (Cu/Co)×20 GMR magnetic multilayers were grown on single crystal (011) Nb that was deposited on (1121) Al2O3 substrates by dc magnetron sputtering. Electron backscatter patterns (EBSPs) revealed that the Cu films display two twin variants, corresponding to two stacking sequences of {111} planes in fcc. The epitaxial orientation relationship between the bcc Nb and both fcc Cu variants was the Nishiyama-Wasserman (N-W) relationship. Conventional TEM observations revealed epitaxial growth for both the Cu/Py/FeMn and (Cu/Co)×20 multilayers. High-resolution TEM confirmed epitaxial growth of close packed (011) Nb on (1120) Al2O3 substrates with [111]Nb∥[0001]Al2O3. Numerous small twins were observed in the Cu near the Cu-Nb interface of the Cu/Py/FeMn multilayer. In the Cu/Co multilayer, the growth planes of the Cu and Co were found to be {100} instead of the expected close-packed {111} planes of the fcc structure.

Synthesis and Characterization of Methylammonium Lead Iodide Perovskite and its Application in Planar Hetero-junction Devices

2018 ◽  
Vol 33 (6) ◽  
pp. 065012 ◽  
Author(s):  
Aditi Upadhyaya ◽  
Chandra Mohan Singh Negi ◽  
Anjali Yadav ◽  
Saral K Gupta ◽  
Ajay Singh Verma
Keyword(s):  
Synthesis And Characterization ◽  
Lead Iodide ◽  
Methylammonium Lead Iodide

Preparation and Characterization of La1Sr2Nb5O10−x Specimens

1990 ◽  
Vol 209 ◽  
Author(s):  
Donald H. Galvàn ◽  
M. Avalos-Borja ◽  
L. Cota-Araiza ◽  
J. Cruz-Reyes ◽  
E. A. Early
Keyword(s):  
High Temperature ◽  
High Resolution ◽  
X Rays ◽  
High Resolution Tem ◽  
Nominal Stoichiometry

ABSTRACTRecently Ogushi et al reported a La-Sr-Nb-O compound with a superconducting temperature of about 225 K. The possibility of having superconductors with such a high temperature is certainly technologically relevant. We prepared specimens with the same nominal stoichiometry and performed characterization by SEM, high resolution TEM, Scanning Auger and X-rays.

Microstructure characterization of a cobalt-oxide-doped cerium-gadolinium-oxide by analytical and high-resolution TEM

2007 ◽  
Vol 55 (8) ◽  
pp. 2907-2917 ◽  
Author(s):  
Zaoli Zhang ◽  
Wilfried Sigle ◽  
Manfred Rühle ◽  
Eva Jud ◽  
Ludwig J. Gauckler
Keyword(s):  
High Resolution ◽  
Cobalt Oxide ◽  
Gadolinium Oxide ◽  
Microstructure Characterization ◽  
High Resolution Tem ◽  
Cerium Gadolinium Oxide

scholarly journals 3-Alkylpyridinium salts from Haplosclerida marine sponges: Isolation, structure elucidations, and biosynthetic considerations

2009 ◽  
Vol 81 (6) ◽  
pp. 1033-1040 ◽  
Author(s):  
Rémi Laville ◽  
Philippe Amade ◽  
Olivier P. Thomas
Keyword(s):  
High Resolution ◽  
Mass Spectra ◽  
Biosynthetic Pathway ◽  
2D Nmr ◽  
Marine Sponges ◽  
Structure Characterization ◽  
Ionization Mass ◽  
Family Structures ◽  
Resolution Electron

A very little studied marine sponge Callyspongia sp. collected off the coast of Martinique was chemically investigated. The study led to the isolation and structure characterization of two new 3-alkylpyridinium salts which belonged to the recently isolated pachychaline family. Structures were elucidated by 1D, 2D NMR and detailed high-resolution electron spray ionization mass spectra (HRESIMS)-MS studies. The use of HRESIMS-MS studies proved to be highly efficient to identify two other close derivatives in a mixture. Finally, these studies allowed us to propose a general biosynthetic pathway leading to important 3-alkylpyridinium salts.

EVOLUTION OF MICROSTRUCTURE AND PHASE COMPOSITION UPON ANNEALING OF LiFePO4 PREPARED BY A LOW TEMPERATURE METHOD

2011 ◽  
Vol 04 (02) ◽  
pp. 117-122 ◽  
Author(s):  
W. ZAJAC ◽  
J. MARZEC ◽  
W. MAZIARZ ◽  
A. RAKOWSKA ◽  
J. MOLENDA
Keyword(s):  
Electrical Conductivity ◽  
Phase Composition ◽  
High Resolution ◽  
Microstructural Characterization ◽  
Temperature Method ◽  
High Resolution Tem ◽  
Iron Valence ◽  
Evolution Of Microstructure ◽  
Type Crystal

The effect of annealing of nanosized LiFePO 4 powder on microstructure, phase composition, iron valence state and electrical conductivity has been studied. Careful microstructural characterization of the as-prepared powder using high resolution TEM revealed presence of {010}-type crystal planes at the surface of crystallites, which seem to be beneficial to electrochemical activity. The second part of the work is focused on explanation of presence and evolution of Fe 3+ detected in the material. Transmission and CEMS modes of Mössbauer spectroscopy together with TEM allowed for ruling out concept of amorphous layers containing Fe 3+ ions covering crystalline LiFePO 4 grains.

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