Beam sensitive materials are important classes of materials in various disciplines, including battery materials, metal–organic frameworks (MOFs), organic−inorganic hybrid halide perovskites, 2D materials, and polymers. Beam sensitive materials have been challenges for conventional TEM chracterization, due to the easy radiation damage by electron beam. Our goal is to investigate beam sensitive materials with maximized contrast, minimum electron beam damage, and atomic resolution structural feature.
This presentation introduces Thermo Fisher advanced transmission electron microscopy (TEM) techniques on the Spectra Ultra platform for characterizing beam sensitive materials. Fast switching the accelerating voltage from 30 to 300 kV with a stabilization time less than 5 minutes makes it possible to optimize the accelerating voltage for the specimen in one microscope session. The massive Ultra-X EDX detector enables the lowest dose STEM EDS element mapping for the materials too beam sensitive for conventional EDS analysis. Integrated differential phase contrast ( iDPC) is the ultimate low-dose STEM technique for directly imaging the light elements down to hydrogen with high signal to noise ratio. Falcon 4i Direct Electron Detector features faster acquisition speeds while maintatining unsurpassed TEM image quality with high signal and low background noise. Combination of Inert gas transfer system (IGST) and cryogenic holder preserves the air sensitive materials in the pristine state, crucial for revealing the intrinsic specimen information. Higher quality atomic TEM data is available from the greater diversity of materials than ever before.
Various battery materials are extremely beam-sensitive. Taking LiCoPO4 (LCP) cathode material as an example, simultaneous ADF and iDPC images resolves that every second lithium site is occupied by the heavy cobalt atom, forming the superstructure at the surface of LCP [ 1].
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