The synthesis of cobalt nanorods and ultrathin gold nanowires by liquid phase process are developed at LPCNO. Such anisotropic metallic particles with controlled length and diameter find applications in several fields like nano-magnetism or nano-electronics. A full understanding of the nucleation and growth is necessary to control the particle morphology and their physical properties. It requires combining in situstudies with high resolution electron microscopy.

Cobalt nanorods (NRs) with optimized magnetic properties thanks to an accurate control of their morphology find application as building blocks for rare-earth free permanent magnets [1,2]. Dense and parallel assemblies of Co NRs were obtained from concentrated suspensions and were compacted into nanostructured materials with strong magnetization and high magnetic anisotropy [3]. A complete description of the Co NRs nucleation and growth steps was established thanks toin situanalysis, theoretical chemistry calculations and probe-corrected electron microscopy. An interesting challenge consists now in shaping sub-millimeter magnets integrated in electronic devices using magnetophoresis methods.

Ultrathin gold nanowires (NWs), exhibiting a diameter lesser than 2 nm and a micrometric length, have attracted expanding interests due to their very high aspect ratio (>1000) with applications for electrical sensors or transparent electrodes [1,2]. The great importance of the ligand shell organization both on the NWs growth and stability was established by in situsmall angle X-ray scattering (SAXS). Their growth was recently followed by in situ high energy X-ray diffraction (HE-XRD) and pair distribution function analysis (PDF). It revealed an unexpected atomic structure of the metal core different from the closed-packed fcc structure of bulk Au making these fascinating objects intermediates between metal and 1D supramolecular organization.

[1] E . Anagnostopoulou et al., Nanoscale 2016, 8, 4020.

[2] M . Pousthomis et al., Nano Research 2015, 8, 2231.

[3] S. Ener et al., Acta Materialia 2018, 145, 290.

[4] A. Loubat et al., Langmuir 2014, 30, 4005.

[5] El S. Nouh et al., Langmuir 2017, 33, 5456.