Structure and Formation Mechanism of Bimetallic Alloy Nanoparticles of Metal Systems Containing Miscibility Gaps and Intermetallics
Co-sputter deposition onto low volatility liquid has been capable of making solid solution alloy nanoparticles.1, 2） In our research, we use co-sputtering onto liquid poly（ethylene glycol）（PEG）（Fig. a）to successfully synthesize solid solution alloy nanoparticles of various metal pairs, including ones with a large miscibility gap, e.g., Au/Pt3） and with intermetallic compounds, e.g., Cu/Au, Cu/Pd, Ag/Pt and Ag/CuPt.4～6） The alloys were obtained for large range of compositions, even those in the gaps and/or for intermetallics.3～5） Furthermore, we found that the particle growth in PEG influences the fine structure and composition of the co-sputtered alloy nanoparticles.3～6） For example, Au/Pt nanoparticles of more Pt are smaller and Pt is richer on the particle surface than at the inside（Fig. b）.3） This is related to stronger binding of Pt to PEG than that of Au to PEG and possibly Au-Au selective attachment during particle growth in PEG. We also found that the composition distributions among single nanoparticles obtained in PEG are relatively broad（Fig. c）.5） This is caused by the effect of the viscous PEG in reducing the particle collision and growth, and thus, the uniformity of the alloy composition.5, 6） The new understanding of particle growth and structure contributes to particle design for novel properties.
1） M. T. Nguyen et al., Nanoscale Adv. 2024, 4, 1822.
2） M. T. Nguyen et al., Soft Matter 2022, 18, 19.
3） L. Deng et al., Langmuir 2020, 36, 3004.
4） M. T. Nguyen et al., Langmuir 2017, 33, 12389.
5） M. Zhu et al., Langmuir 2021, 37, 6096.
6） M. Zhu et al., Mater. Adv. 2022, 3, 8967.
Mai Thanh Nguyen Faculty of Engineering, Hokkaido University