Robust synthesis of gold rhombic dodecahedra with well-controlled sizes and their optical properties

Through the seed-mediated growth method in N,N-dimethylformamide (DMF)-water medium using trisodium citrate and poly(vinyl pyrrolidone) (PVP) as stabilizer, Au rhombic dodecahedra with a narrow size distribution (< 5% in standard deviation) and high shape yield (> 90%) could be reproducibly synthesized thanks to the robust formation of rhombic dodecahedra by DMF-water medium and surface stabilization by trisodium citrate. Moreover, the edge lengths of these Au rhombic dodecahedra could be readily controlled from 19 to 67 nm by varying the amount of seeds, concentration of HAuCl₄, or both, and thus the localized surface plasmon resonance peak positions of the Au rhombic dodecahedra could be continuously tuned from 532 to 655 nm.