Spray pyrolysis synthesis of ZnS nanoparticles from a single-source precursor

Abstract

ZnS, a II–VI semiconductor with a relatively high direct bandgap (∼3.6 eV) in the near-UV region, has potential applications in areas such as solar cells, lasers anddisplays. In addition, ZnS nanoparticles can be applied as phosphors, probes forbioimaging, emitters in light emitting diodes and photocatalysts. Here, we report synthesisof cubic ZnS nanoparticles from a low-cost single-source precursor in a continuousspray pyrolysis reactor. In this approach, the evaporation and decomposition ofprecursor and nucleation of particles occur sequentially. Product particles werecharacterized by HRTEM, XRD, and EDX. Particles with diameters ranging from 2 to7 nm were produced. HF was used to remove ZnO impurities and other surfacecontamination. As-synthesized ZnS nanoparticles exhibit blue photoluminescencenear 440 nm under UV excitation and have quantum yields up to 15% after HFtreatment. This demonstrates a potentially general approach for continuous low-costsynthesis of semiconductor quantum dots for applications where tight controlof the size distribution is less important than scalable, economical production.