Monodispersed wurtzite Cu2SnS3 nanocrystals by phosphine and oleylamine free facile heat-up technique

Abstract

Wurtzite Cu₂SnS₃ (CTS) nanocrystals with an average size 8.5 nm were prepared for the first time by a phosphine and oleylamine free facile one-step thermolysis method. The as-prepared nanocrystals were investigated for structural, morphological and compositional properties. The advantages of the heat-up technique for a swift synthesis of gram scale, phase pure CTS nanocrystals; applicable for various energy devices like solar cell, batteries etc., are discussed. Nanocrystals were synthesized at different reaction times viz. 10, 20 and 30 minutes. The possible growth mechanism for colloidal CTS nanocrystals has been investigated. Herein we observed that CTS nanocrystals growth starts with the formation of copper sulphide nanoparticles, acting as nuclei for the subsequent growth of CTS nanocrystals. X-ray diffraction analysis revealed the formation of phase pure wurtzite CTS nanocrystals which is further supported by high resolution transmission electron microscopy, selected area electron diffraction and energy dispersive X-ray analysis. To the best of our knowledge colloidal wurtzite CTS nanocrystals synthesis has been reported with the use of strongly co-ordinating, highly toxic oleylamine (OLA) solvent, herein stepping towards a green synthesis we report for the first time on the synthesis of sub 10 nm wurtzite CTS nanocrystals using neutral, less toxic and less expensive octadecene (ODE) solvent.