Influence of silver precursor concentration on structural, optical and morphological properties of Cu1-xAgxInS2 semiconductor nanocrystals

Abstract Near-Infrared (NIR)-emitting Cu 1-x Ag x InS 2 ( x  = 0.0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0 mmol) semiconductor nanocrystals were synthesized from CuCl, AgNO 3 and InCl 3 precursors by varying the concentrations of silver precursor (0 ≤  x  ≤ 1.0) using 1-dodecanethiol as capping agent by hot injection method. In CuInS 2 host lattice, the incorporation of Ag + ions can be identified by the change of color from black (CuInS 2 ) to dark brown (AgInS 2 ). The absorption band-edge of the synthesized nanocrystal has shifted to blue-shift by changing the silver composition in Cu 1-x Ag x InS 2 nanocrystals. The optical band gap (E g op ) of synthesized nanocrystals increased with incremental change of silver ion concentrations. The structural, morphological and elemental compositions of the synthesized nanocrystals were studied using X-ray diffraction (XRD), High-resolution transmission electron microscope (HR-TEM) and Energy dispersive x-ray (EDX) spectroscopic analysis.