Radiological Control of Gold Octahedral and Prism Nanoparticles

摘要

We report on the fundamental morphology growth of gold-based nanoparticles by solution radiolysis. The radiolysis experiments utilize γ-irradiation by the ~(60)Co source of 1.345 × 10~5 Ci at Sandia National Laboratories Gamma Irradiation Facility (GIF). Radiolysis of pure gold-polymer solutions with different dose rates and aging time is studied with a focus on the formation of gold nano-octahedra and nano-prism particles. Nanoparticle characterization techniques included are UV-vis and TEM. The data analysis shows that the dose rate dictates the size of the gold nanoparticles formed, similar to that observed in earlier silver studies. At high dose rates, all reducing species are produced and scavenged within a short time, and then coalesce into separate nanoparticles. At low dose rates, the coalescence process is faster than the production rate of the reducing radicals. The reduction of radicals occurs mainly on clusters already formed. The differences in the resultant nanoparticles' morphology occur due to a combination of dose rate, post irradiation particle aging, and lack of radical scavengers (e.g. isopropyl alcohol), resulting in either gold nano-spheres, octahedral or prism nanoparticles. The progressive evolution with dose rate of the UV-visible absorption spectra of radiation-induced metal clusters is discussed.