Modulation of structures of CuInS2 nanoparticles grown with ethylxanthate salts

• Chalcopyrite, wurtzite and zincblende of CuInS2 nanoparticles were grown.
• Wurtzite or zincblende of CuInS2 was controlled by the nucleus structures.
• CuInS2 from wurtzite to chalcopyrite were tuned by the ligand ratios.
• The mechanisms of phase selectivity have been demonstrated.

Chalcopyrite, wurtzite and zincblende structured CuInS2 nanoparticles of 2.6–11.4 nm with high quality and strong luminescence were successfully synthesized by decomposing ethylxanthate salts. The effects of ligands and nucleus structures on nanoparticle structures and properties were studied. The nanoparticle structures could be adjusted by controlling the nucleus structures through tuning the injecting sequences of Cu–S and In–S precursors. The nanoparticle structures could also be adjusted to be wurtzite or chalcopyrite by adjusting the capping ligand ratio of tri-n-octylphosphine/oleic acid/oleylamine. An increase in tri-n-octylphosphine ratio would induce the selective growth of chalcopyrite structured CuInS2 nanoparticles. The mechanisms in CuInS2 crystal structure selectivity were discussed, which provides an insight into controlled synthesis of other ternary chalcogenides.

XRD patterns of zincblende and wurtzite CuInS2 nanoparticles synthesized in the TOP/OA/OLA ratio of 1:1:1; (a) by injecting Cu(exan)2 first and then injecting In(exan)3 1 min later and lasted for 30 min; (b) by injecting In(exan)3 first and then injecting Cu(exan)2 1 min later and lasted for 30 min. XRD patterns of (c) wurtzite structured CuS grown by injecting Cu(exan)2 only for 1 min; (d) cubic structured In2S3 nanocrystals grown by injecting In(exan)3 only for 1 min.Figure optionsDownload as PowerPoint slide