One-pot facile synthesis of a concentrated Si nanoparticle solutionElectronic supplementary information (ESI) available. See DOI: 10.1039/c3cc43846e

A silicon nanoparticle solution (size ≅ 50 nm) with the concentration of 100 mM, which is contamination free, was synthesized using a ball milling method and was stable for 4 months without aggregation. This stability was responsible for large negative zeta potential on the surface of Si-NPs, established by milling in 2-propanol solvent. A silicon nanoparticle solution (size ≅ 50 nm) with the concentration of 100 mM, which is contamination free, was synthesized using a ball milling method and was stable for 4 months without aggregation.