Low-Voltage Electron Microscopy for Characterizing Core-Shell Nanoparticles

The LVEM 25E is the ideal choice for in-lab advanced materials analysis such as the characterization of core-shell nanoparticles.

Core-shell nanoparticles are innovative materials combining the unique properties of two substances. For instance, gold-silica nanoparticles, which feature a gold core surrounded by a silica shell, deliver enhanced stability, tailored optical and magnetic properties, biocompatibility, and controlled sizing. LVEM offers precise, high-contrast images along with detailed elemental analysis. With its multi-modal capabilities, TEM, STEM, SEM, and EDS, the LVEM 25E enables comprehensive studies of morphology, composition, and synthesis quality in a compact and accessible format.

Silica-Coated Gold Core-Shell Nanoparticles

TEM, Dark field STEM, SEM, and STEM EDS mapping all captured with the LVEM 25E, compact all-in-one electron microscope.

A study conducted by Beaulieu (2024) utilized the LVEM 25E to investigate the size, morphology, and elemental composition of Au–Si core-shell nanoparticles. The results underscored the microscope’s effectiveness in nanoparticle characterization, highlighting its versatility across multiple imaging and analysis modes. Commercial Au-Si particles were analyzed using TEM, STEM, SEM, and EDS modes, with sample preparation tailored for each technique.

In TEM mode, the LVEM 25E provided clear structural contrast between gold cores and silica shells at high magnifications, allowing accurate dimensional analysis and confirmation of particle uniformity. Adjustments in contrast settings enhanced the visualization of core-shell layers, a crucial feature for analyzing heterogeneous materials.

The STEM mode further validated the structural observations, with imaging conducted at both 10 kV and 15 kV. The dual-voltage capability proved critical, as 10 kV minimized beam damage in sensitive samples while 15 kV offered slightly higher beam penetration for denser regions.

The SEM mode highlighted the gold cores with bright contrast using the instruments backscattered electron detector. An advantage noted in the study was the compatibility of TEM grids with SEM imaging, reducing preparation time and simplifying work flow.

Elemental analysis using STEM-EDS mapping confirmed the presence and localization of gold and silica, with distinct color-coded maps (gold in yellow, silica in blue) aligning with structural features. EDS spectrum revealed characteristic peaks for both elements, providing further validation of the sample composition.

Conclusion

The study found that the LVEM 25E’s ability to characterize core-shell nanoparticles with precision and efficiency. Its multi-modal flexibility ensures that researchers can evaluate morphology, composition, and synthesis quality using a single instrument. This makes the LVEM 25E an indispensable tool for nanomaterial research, quality control, and advanced applications in fields like drug delivery and materials engineering.

Beaulieu, M. (2024). LVEM25E for Multi-Modal Au@Si Core-Shell Characterization. Delong America. Unpublished study.