Structural and optical analysis of single phase CuInS2 nanocrystals for solar cell applications

Nanostructured phase pure CuInS2 particles have been successfully synthesized by solid state melt growth method. The crystallographic structure, morphological, chemical composition and optical properties of synthesized sample have been characterized by various analytical techniques, includes X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDAX), UV-vis-NIR diffuse reflectance spectroscopy and photoluminescence spectroscopy. From the XRD spectra chalcopyrite structure of CuInS2 sample with phase pure nano particles is confirmed. Annealing promotes the grain size and crystallinity of the CuInS2 sample and is clearly indicated by XRD analysis. The optical band gap energy of CuInS2 sample is calculated to be 2.61 eV, which has also been confirmed by photoluminescence spectroscopy. SEM micrograph shows that the CuInS2 sample is composed of particles ranges from 25-50nm in size. Annealed sample confirms the increase of particle size up to 85 nm. Compositional stability of CuInS2 phase pure nano particles have been studied by thermo gravimetric analysis. The effect of annealing temperatures on the structural and morphological properties of CuInS2 nanocrystals synthesized by solid state reactions has also been studied in this report. (C) 2016 The Japan Society of Applied Physics