| Metal nanoparticles possess optical, electrical, magnetic, and other physical and chemical properties which will be significantly tunedt with the change of morphology and size uniformity. High uniformity in terms of shape and particle sizes, i.e., monodisperse, is critical to their applications. Chemical methods, bottom-up routes, are mainly adopted to synthesize monodisperse metal nanoparticles. However, it usually requires organometallic precursors with high reactivity or reducing agents, and the processes are complicated and contaminated. Therefore, the development of a top-down physical method to synthesize monodisperse metal nanoparticles is important.In this work, we converted directly bulky IIB metals to ligand-protected, highly crystalline, monodisperse spherical colloidal Cd nanoparticles with precisely controlled sizes(6.5–16.8 nm, size dispersion ? < 10%), using nanosecond pulsed laser ablation/irradiation in liquid. We have also studied formation mechanism of the monodisperse Cd nanoparticles. The experimental results and related thermodynamic calculations show that it is based on near-IR-laser-induced size-selectively layer-by-layer surface vaporization, and the size can controlled by laser fluence. In addition, the use of OA made a big difference in the process of homogenization. In a word, it is a simple and environmentally friendly process to synthesize monodisperse colloidal metal nanoparticles.Furthermore, we used the same method to achieve a controlled preparation of monodisperse colloidal Zn nanoparticles, which validated the mechanism of near-IR-laser-induced size-selectively layer-by-layer surface vaporization. And we synthesized ZnSe hollow nanospheres using Zn nanoparticles as templates.At last, we found that the monodisperse Cd nanoparticles displayed pronounced deep-UV localized surface plasmon resonance, which was confirmed by both experimental results and FDTD simulation, making them useful for ultrasensitive biomolecular detection. |
PDF Full Text Request