One-Pot Synthesis of Ultrasmooth, Precisely Shaped Gold Nanospheres via Surface Self-Polishing Etching and Regrowth

摘要

Despite many seeded methods having been achieved to synthesize spherical nanoparticles, the one-pot synthesis of Au nanospheres with perfect morphology is still a challenge due to nanocrystals tending to adopt a polyhedral morphology to minimize their surface free energy. We present here a one-pot synthesis for precisely shaped and monodispersed single-crystalline Au nanospheres with an ultrasmooth surface and tunable sizes (30–100 nm). During the synthesis, Au nanospheres undergo a unique morphology change from octahedral to spherical shape via selectively surface self-polishing etching induced by the O_(2)/Cl~(–) pair and Ag ion dynamically tailored regrowth direction. The localized surface plasmon resonance property of the Au nanospheres with different sizes is found to match well with the theoretical prediction because of their perfect spherical shapes and uniform sizes. Moreover, this protocol can achieve a large-scale synthesis (more than 500 mL for one time) of Au nanospheres solution with extreme stability due to isotropic surface tension (stored in ethylene glycol for more than 24 months). Such fundamental findings open up unique insights into the formation mechanism of Au nanospheres with precisely controlled size and shape, and they could be useful for the synthesis of other nanospheres.