From nanoplates to microtubes and microrods: a surfactant-free rolling mechanism for facile fabrication and morphology evolution of Ag2S films.

By a simple and facile wet-chemistry technique without any surfactant, various shapes of Ag(2)S crystals--including leaflike pentagonal nanoplates, crinkly nanoscrolls, hexagonal prismlike microtubes, and microrods--were fabricated in situ on a large-area silver-foil surface separately. Detailed experiments revealed that the Ag(2)S nanoplates were formed just by immersing the silver foil in a sulfur/ethanol solution at room temperature and atmospheric pressure, and they subsequently rolled into nanoscrolls and further grew into microtubes and microrods under solvothermal conditions. Inspired by the natural curling of a piece of foliage, we proposed a surfactant-free rolling mechanism to interpret the observed morphological evolution from lamellar to tubular structures.