Nanoparticle size and 3D shape measurement by electron tomography: An Inter-Laboratory Comparison
Misa Hayashida1, Francisco Paraguay-Delgado2, Carlos Ornelas2
1Nanotechnology Research Centre, National Research Council of Canada, 11421 Saskatchewan Drive, Edmonton, AB, T6G2M9, Canada.
Micron (Oxford, England : 1993)
|October 29, 2020
Summary
This study assessed the repeatability and reproducibility of electron tomography (ET) for measuring nanoparticle (NP) size and shape. Results showed high agreement between laboratories, with key parameters showing less than 7% disagreement.
Area of Science:
- Materials Science
- Nanotechnology
- Metrology
Background:
- Electron tomography (ET) is established for 3D quantitative measurements.
- Systematic evaluation of ET's repeatability and reproducibility for nanoparticle characterization is lacking.
- Standardized protocols are crucial for reliable nanoscale measurements.
Purpose of the Study:
- To evaluate the reproducibility and repeatability of a standardized electron tomography protocol for measuring nanoparticle (NP) size and 3D shape parameters.
- To perform an inter-laboratory comparison (ILC) involving multiple labs and instruments.
- To quantify the influence of factors like the missing wedge effect and beam-induced movement.
Main Methods:
- An inter-laboratory comparison (ILC) involving six laboratories and six different electron tomography instrument models.
- Measurement of gold nanoparticles (30 nm nominal diameter) using a standardized protocol (ISO technical specification).
- Utilized rod-shaped carbon supports to mitigate the missing wedge effect for improved quantification.
Main Results:
- Measurements of nanoparticle parameters including Volume (V), maximum Feret diameter (Fmax), minimum Feret diameter (Fmin), volume-equivalent diameter (Deq), and aspect ratio (Frat) were compared.
- Maximum disagreement for Fmin and Fmax between participating labs was within 7%.
- Measured Deq (27.5 nm - 30.3 nm) aligned with the manufacturer's specification (28 nm - 32 nm).
Conclusions:
- The standardized electron tomography protocol demonstrates good repeatability and reproducibility for nanoparticle size and shape measurements across different laboratories and instruments.
- The study successfully quantified the impact of the missing wedge effect and beam-induced nanoparticle movement on measurement accuracy.
- Findings support the reliability of ET for quantitative nanoparticle metrology when standardized protocols are followed.
