Abstract
In 2 Se 3 is an essential phase change material and CuInSe 2 is the fundamental basis of the copper-indium-gallium- diselenide (CIGS) solar energy material. In this paper, we demonstrate the feasibility to transform the phase change material to the solar energy material via the solid state reaction. The In 2 Se 3 nanobelts (NBs) were synthesized via the vapor-liquid-solid mechanism. The chemical composition and the optical properties were investigated by energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and reflectance and photoluminescence spectra. In the in situ observation of the solid state reaction with Cu to form the CuInSe 2 NBs with ultrahigh vacuum transmission electron microscopy, we observed the In 2 Se 3 /CuInSe 2 transformation at atomic scale in real time. The progression of the atomic layer at the interface provided the pertinent information on the kinetic mechanism. In 2 Se 3 /CuInSe 2 nano-heterostructures were also obtained in the present investigation. The approach to the CIGS nanosolar cell was also proposed. This study shall be beneficial in the development of high-performance nanowire solar cells and nanodevices with In 2 Se 3 /CuInSe 2 nano-heterostructures. © 2011 American Chemical Society.