High-resolution electron microscopy and electron diffraction of perovskite-type superconducting copper oxides

Abstract

High-resolution electron microscopy and electron diffraction are quite useful for structural characterization of perovskite-type superconducting copper oxides on the atomic scale. Valuable information on the crystal structures and the microstructures could be obtained from observed high-resolution images if severe conditions such as thinner crystals and definite defocus values are satisfied. The structure images and electron diffraction patterns include information not only on accurate atomic coordinates of cations but also on ordered arrangements of oxygen atoms and oxygen vacancies. Crystal structures of the various perovskite-type copper oxides were analyzed from the observed structure images. Modulated structures, defects, intergowth, surfaces, and interfaces were also investigated.

Crystal Structures of CH3NH3PbI3 and Related Perovskite Compounds Used for Solar Cells

“…High-resolution TEM observations have been performed for the perovskite materials [20], and the nanostructures were discussed. Although TEM is a powerful tool for nanostructured materials, sample damage by electron beam irradiation should be avoided, because the CH 3 NH 3 PbI 3 are known to be unstable during annealing at elevated temperatures.…”

Crystal structures of perovskite halide compounds used for solar cells

“…Although single crystal XRD is suitable for atomic structure determination, actual solar cells have thin film configurations and microcrystalline structures, and Rietveld refinements are one of the good analysis methods to determine the crystal structure of the perovskite compounds in the actual solar cell device configurations. Electron diffraction and highresolution transmission electron microscopy are also effective instruments to analyze nanostructures of the solar cell materials [111][112][113][114] and crystal structures of the perovskite compounds [115][116][117].…”

Fabrication and Characterization of Element-Doped Perovskite Solar Cells

“…Since these perovskite-type materials often have nanostructures in the solar cell devices, information on the crystal structures, fabrication, and characterization would be useful for fabrication of the perovskite-type crystals. Transmission electron microscopy, electron diffraction, and high-resolution electron microscopy are powerful tools for structure analysis of solar cells [20] and perovskite-type structures in atomic scale [21][22][23].…”

“…a) is a high-resolution TEM image of the CH 3 NH 3 PbI 3 taken along the a-axis[33]. The images of thinner parts of the crystals indicate the direct projection of the crystal structure[21,22]. The darkness and the size of the dark spots corresponding to Pb positions could be directly identified, and atomic positions of iodine (I) in the crystal indicate weak contrast, as compared with the projected atomic structure model of CH 3 NH 3 PbI 3 along the [100] direction inFigure 7(b).…”