Vacuum technique of nanodiamond dispersing on a substrate from an aqueous suspension.

This article focuses on a novel vacuum technique for depositing diamond nanoparticles (DNPs) from aqueous suspensions onto substrates, enabling controlled low-density distributions suitable for individual nanoparticle characterization and manipulation. Using detonation nanodiamonds (DNDs) functionalized with carboxyl groups, the study demonstrates that reducing the initial suspension concentration allows achieving densities of ≤1 particle per μm² across the substrate. The method involves rapid freezing and sublimation of water under vacuum, which prevents nanoparticle agglomeration by immobilizing particles in ice and results in a radial distribution with higher nanoparticle concentration near the drop center due to particle migration during freezing. Atomic force microscopy was employed to analyze spatial distributions, confirming the technique’s effectiveness for applications in nanosensors, quantum optical devices, and integrated photonics.