Five-fold twinned pentagonal gold nanocrystal structure exclusively bounded by {110} facets

Monodispersed five-fold twinned gold (Au) nanocrystals (NCs) with a pentagon (Pg) morphology exclusively bounded by {110} facets have been prepared through a PVP-assisted seed-mediated growth in N,N-dimethylformamide (DMF). Low water concentration, low reaction temperature and existence of DMF have been confirmed to play important roles in achieving the {110}-facet-bounded Au Pg NCs. A possible evolution process from Au decahedron (Dh), via {110}-facet-truncated decahedron (TD), {110}-facet-heavily-truncated decahedron (HTD) and pentagonal star (PS) to final Pg has been suggested to understand the formation of the Pg Au nanocrystals in the DMF reaction system.