Singular MoS2, SiO2 and Si nanostructures—synthesis by solar ablation

Abstract

Solar ablation creates the sharp radiative and temperature gradients, as well as the high-temperature annealing environment, that favor nanomaterial syntheses. Using highly concentrated sunlight, we generated fullerene-like MoS₂, ranging from single-walled nanotubes and closed-cage structures to their larger multi-walled counterparts. TEM, HRTEM and EDS unambiguously established the nanostructures, some achieving fundamentally minimum sizes predicted by molecular structural theory. Irradiation of MoS₂ and powdered mixtures of MoS₂ + SiO₂ in evacuated quartz ampoules also generated nanofibers and nanospheres of amorphous SiO₂: the first production of SiO₂nanostructures purely from quartz. Also, solar ablation of MoS₂ + SiO mixtures produced nanowires and nanospheres of crystalline Si.