Synthesis of zincblende CuInS2 and Fe-substituted CuInS2 by the reaction of binary colloids

Abstract Colloidal suspension of binary sulfides of copper and indium were generated by the reaction of CuCl and In 2 (SO 4 ) 3 with thiourea independently in ethyleneglycol. The colloids were identified to be Cu 9 S 5 and a mixture of InS and In 2 S 3 from the TEM-SAED measurements. They were reacted to yield phase pure CuInS 2 in zincblende arrangement as endorsed by the powder X-ray diffraction pattern, TEM-SAED, lattice fringe measurements and Raman spectroscopy measurements. Optical band gap of zincblende CuInS 2 was measured using UV–visible spectroscopy. In the photoluminescence spectrum, a strong emission centred at around 750 nm was observed on exciting the sample with λ  = 500 nm. Following this success, quaternary composition containing Cu, In, Fe and S in zincblende arrangement has been synthesized and characterized. Band gap of iron substituted samples was estimated to be 1.07 eV. It showed paramagnetic behaviour at room temperature suggesting its use as opto-magnetic material. While cubic CIS degraded methylene blue dye solution under visible light radiation, iron substituted sample did not promote this reaction.