Facile phase and composition tuned synthesis of tin chalcogenide nanocrystals

Abstract

We synthesized polytypic tin sulfide, SnS, Sn2S3, and SnS2 nanocrystals, by means of novel gas-phase laser photolysis of tetramethyl tin and hydrogen sulfide. A facile composition tuning through the pressure of precursors (addition of dimethyl selenium) yields a series of orthorhombic phase SnX and hexagonal phase SnX2, where X = SxSe1-x with 0 <= x <= 1. Various polytypic hybrids such as SnS-Sn2S3-SnS2, SnS-SnS2, Sn2S3-SnS2, and SnSe-SnSe2 were synthesized. This resulted in the ability to tune the band gap over a wide range (1.0-2.3 eV). Their photon energy conversion properties were investigated by fabricating photodetector devices using the nanocrystal-reduced graphene oxide nanocomposites. The enhanced photoconversion efficiency was observed from the polytypic hybrid nanostructures. This original synthesis method for tin chalcogenide nanocrystals is expected to help expand applications in high-performance energy conversion systems.