Characterization on Three-Dimensional Trajectory of Disk-Like Gold-Nickel-Platinum Nanomotor Using Digital Holographic Imaging

Self-propelling disk-like nanomotor consisting of three metallic segments: a non-catalytic gold (Au), central magnetic nickel (Ni), and a catalytic platinum (Pt), is designed and fabricated with a high-efficiency layer-by-layer (LbL) deposition method based on the nano-electro-mechanical systems (NMES) technology. A bubble propulsion mechanism, resulting from bubble growth and collapse, is proposed to explain the locomotion of the nanomotor suspended in hydrogen peroxide (H₂O₂) solution. The autonomous propulsion of Au-Ni-Pt nanomotor is characterized by digital holographic imaging and analyzed using Matlab, revealing that oxygen (O₂) bubbles are generated and detached from the surface of Pt. In addition, the holographic images are for the first time used to reconstruct the instantaneously three-dimensional (3D) location and trajectory of the nanomotor.