Synthesis and characterization of CuInS2 nanocrystals prepared by solvothermal/molten salt method

• Published in: Ceramics international 2016-07, Vol.42 (9), p.11303-11308
• Main Authors: Benchikhi, Mohamed, El Ouatib, Rachida, Er-Rakho, Lahcen, Durand, Bernard
• Format: Article
• Language: English
• Subjects: Crystallization; CuInS2; Molten salt method; Nanocrystal; Solvothermal synthesis
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2016.04.048

Highly crystallized CuInS2 (CIS) nanocrystals were successfully synthesized using a molten-salt method with CuInS2 nanoparticles as precursors. The ultrafine precursors have been synthesized by the solvothermal reactions of metal chlorides and thiourea in ethylene glycol in the presence of sodium hydroxide. The effects of reaction temperature, dwell time and salt to reactant ratio on the crystallinity and morphology of CuInS2 powders were investigated. The powders were characterized by X-ray diffraction, transmission electron microscopy, BET surface area measurements, energy dispersive X-ray spectroscopy and UV–vis absorption spectroscopy techniques. Crystallizations carried out at 550°C for 6h with KSCN/CuInS2=3.75M ratio lead to a powder formed of nanocrystals with a size in the range 25–35nm and exhibits a specific surface area close to 35m2/g. EDS results showed the formation of stoichiometric CuInS2 nanocrystals. The UV–vis absorption spectrum showed that the CuInS2 nanocrystals had a good absorbance in visible region with a band gap close to 1.5eV, which is in the range desirable for photovoltaic applications.