Search

The study demonstrates a new method to quantify Secondary Ion Mass Spectrometry (SIMS) data by using a synergetic combination of Energy Dispersive X-ray spectroscopy (EDX) and SIMS. The novelty of this approach lies in using a diffusion couple to produce a continuum of concentration variation to cover a large portion of the composition space (100 at% to sub-1000 ppm) in a single sample. Furthermore, this approach encompasses the concentration-dependent Relative Sensitivity Factor (RSF) which is essential when the concentrations span several orders of magnitude. By correlating EDX and SIMS profiles, the SIMS signal intensity can be converted to concentrations far below the detection limit of the EDX technique. [ABSTRACT FROM AUTHOR]

It is shown experimentally that the near-infrared femtosecond laser irradiation and subsequent thermal treatment of silver-containing silicate glasses result in the formation of luminescent silver molecular clusters (MCs) and silver nanoparticles (NPs). In glasses doped also with halides (mostly Br), the nonluminescent silver NPs are formed because of the presence of halogenide shells on their surfaces, whereas, in glasses with no Br ions, the luminescent silver nanoparticles provides an emission in the 600- to 750-nm range. Two possible mechanisms of luminescence of glass with silver NPs are considered: (i) luminescence of silver NPs without halogenide shell and (ii) the luminescence of silver MCs Agm (m=1 to 4) remaining even after the formation of silver NPs. [ABSTRACT FROM AUTHOR]

Degradation mechanisms in LiV 3 O 8 cathode films (~500 nm) with different initial microstructures i.e., globular nanocrystals in amorphous matrix and needle-like nanocrystals, synthesized by annealing the cathodes at 150 °C and 300 °C for 6 h are studied by Transmission Electron Microscopy (TEM) and Auger Electron Spectroscopy (AES). In addition, a unique in-situ combination of TEM and Secondary Ion Mass Spectrometry (SIMS) imaging techniques, namely Parallel Ion and Electron beam Spectrometry (PIES) is carried out to measure the 3D distribution of V and Li with nanoscale resolution. These characterization studies focus on correlating the pre- and post-cycling microstructure to observed electrochemical performance. The LiV 3 O 8 cathode film with needle-like nanocrystals (300 °C) shows a higher initial capacity but it degrades rapidly compared to the film with globular nanocrystals embedded in amorphous matrix (150 °C). We observed that LiV 3 O 8 films with needle-like nanocrystals are more susceptible to cathode decohesion and vanadium dissolution than the films with globular nanocrystals embedded in amorphous matrix, explaining the differences in their electrochemical performance. The findings from this study have relevance to the development of thin film electrode microstructures for high capacity and cyclic stability. Image 1 • Microstructural effects on degradation mechanisms in LiV 3 O 8 thin films was studied. • Used correlative electron and ion microscopy for nano-scale microstructural studies. • Amorphous + nanocrystalline composite cathode exhibited higher cyclic stability. • A higher initial capacity that faded faster in needle-like nanocrystalline cathodes. • Faster capacity fade is due to higher V dissolution and cathode decohesion. [ABSTRACT FROM AUTHOR]